Spotlight: Bane Lord Tartarus

We’ve got a treat for you guys today, here’s an article by Lazarus0909 on the Privateer Press Forums!  Behold, Bane Lord Tartarus!

———-

Ah Bane Lord Tartarus… one of the most powerful and hated solos in the game. Also known as Tartarus, BLT, Tartarsauce (or The Sauce) and of course “I hate that guy”. So I guess it’s time for another spotlight….

Overview:

Tartarus has some pretty ridiculous stats if we’re honest, especially for a solo and even more so considering his abilities. In fact most of his stats are actually pretty comparable to your average Cryx heavy the Slayer, sharing the same good SPD, MAT, DEF and ARM values (well good ARM for Tartarus anyway). However I will point out that Tartarus is still quite a long way from being invincible, sitting on a medium base which can make him tough to screen, especially when you consider how much good opponents will be trying to kill him. If you view him as a tougher combat solo and not a heavy tank, you should do ok. Even then many of these stats are pretty misleading given his many abilities and special rules, of which he has… 11! I counted…. Ridiculous, I know. Tartarus then is decently durable for a solo, packing a respectable 8 boxes and coming built in with a number of ways to keep him alive for a pretty unfair cost of 4 points.

As always, the Battle College article can go over many of the basics.

Weapon: Rivener

Rivener is an excellent weapon, swinging at MAT 7 and packing Reach, Weapon Master and the awesome Thresher *Attack into a decent POW 12 hit. All of this seems pretty good by itself, but factor in his own Curse (bumping the MAT up to 9), Dark Shroud (essentially bumping the POW up to 14) and the insane Death Toll rule, and Tartarus can generally slaughter almost any infantry in the game without much difficulty. Despite being such an attractive weapon, a few things do need to be considered, namely whether Tartarus is getting overextended using it (an easy trap to fall into) and the possibility to inflict friendly casualties as Thresher does not discriminate. As always then, positioning is everything to get the most out of Tartarus’ combat abilities, but we’ll get there soon enough. One final interesting point on Rivener – despite being a named weapon, on a character solo, it isn’t magical. Interesting eh?

Ability: Death Toll [Small-based Bane]

He can make MOAR Banez! Essentially Death Toll works like this – for each living model that Tartarus destroys, a grunt can be added to a friendly Bane unit, so long as the new models are placed within 3” of Tartarus and in CMD range of the unit leader. Note that any models he kills are Removed From Play (RFP) so be careful if you were counting on gathering any Soul or Corpse tokens, as his ability specifically prevents them being gathered. This ability is so awesome, even regulars cannot believe how ridiculous this is. Not only can you slaughter a bunch of models with Tartarus, but you can create new Banes of your own, giving you a generous attrition swing and possibly wreaking further havoc, because yes, those new models can activate that turn! The other great thing about this ability is it can often extend both the threat range and the charge angles of the original unit with new model placement, allowing you to catch targets of opportunity that you otherwise could not. Generally then, Tartarus will want to go first, putting down Curse (below) and threshering up some Banes before the unit activates for maximum effectiveness. Finally, notice the wording “small-based bane”; Tartarus cannot go around making more Bane Riders. Ah well…

Ability: Curse [Bane]

Widely considered to be his bread and butter ability, cursing (like a sailor) is what Tartarus usually spends much of his time doing in any given game. Curse is a RNG: CMD any time ability that lasts for one turn (no affecting free strikes), doesn’t require a roll to hit, and grants Bane’s charging a cursed model +2” of movement, as well as letting any Bane attacking the affected models swing with +2 MAT. Unlike Death Toll, this ability works for any Bane unit, so even Riders can benefit as well. This is what you usually bring Tartarus for in any given list, helping the Banes overcome their average SPD of 5 with further threat range and increasing their MAT to 8 in melee combat. A fantastic ability that helps make up for some of the weaknesses Banes have, and generally worth keeping Tartarus safe for, so he can continue applying it each turn. Finally there is a common misconception among new players: you cannot run and curse (activation ends after running). However, you can curse one unit and charge another, Tartarus can charge then curse, and he gets the benefits of curse as well.

Ability: Dark Shroud

Helping keep with the destructive melee theme, Tartarus also comes built in with Dark Shroud like the other Bane Thralls, helping to share this ARM debuff around to any model in his melee range as well as upping his own damage output. Like the other Cryx models with this ability, Dark Shroud is fantastic for bringing harder targets down, and it will often be worth running a single model with this ability into melee range of anything that really has to die, especially if you have other models free to take it out. Note that with a medium base and Reach, Tartarus can spread this debuff through a decently wide area.

Ability: Ghostly

Tartarus also has Ghostly, an ability he shares with Bane Knights. This is a crucial ability for him, allowing him to get through any difficult piece of terrain without a hitch as well as ignoring free strikes when trying to bury deep into a unit for a good thresher or escape being jammed in melee. Because he is a solo and not a UA, this is especially helpful as it means Tartarus can operate without Saxon/Ghost Walk support, helping him remain independent, reduce resource use and of course operate further away from those key models.

Ability: Stealth

One of the most important abilities on his card, Stealth is usually the only thing keeping Tartarus alive from an opponent that is desperately trying to kill him. This prevents Tartarus from getting shot up while he makes his way across the table, allowing him to hopefully survive long enough to get off a decent turn of cursing and, ideally, a juicy charge. As always, beware of abilities like Mage Sight, True Sight and the common Eyeless Sight that will ignore this ability altogether, as well as Sprays and higher POW boosted AOES that stand a chance of killing him with a decent spike.

Ability: Terror

Tartarus is like many Cryx models in sharing the ability to frighten opposing models. This is an easy-to-forget ability that can occasionally be game winning, especially considering how often Tartarus will end up in melee combat. Force an opponent to take enough terror checks and they are bound to fail a couple, so this can swing a game pretty quickly if the dice turn against the other player. Bear in mind Undead, Fearless and other similar abilities that ignore this altogether.

Ability: Undead

Like many Cryx models, Tartarus is undead, helping to keep him safe from numerous terror inducing effects as well as the many abilities out there that only affect living models. As Cryx players, we all know how this works, so moving onto…

Ability: Commander

Because I guess they felt Tartarus didn’t have enough special rules already? In all my many games with Tartarus, I have honestly never had this come up, mostly due to any of my living viable models rarely getting scared, too far away or simply dead before it’s had the chance to come into play. Better than nothing mind, and with a high CMD of 9, Tartarus can certainly come to the rescue if your living models decide to bolt.

Uses:

Whew, that was a long list. Tartarus is a surprisingly multi-functional solo, packing a lot of different abilities into a single card, but generally he has a relatively straightforward gameplan that usually consists of balancing 3 main considerations:

• Staying alive – Tartarus is usually top on your opponent’s list for models to kill, so one of the most important things to do with him on a given turn is making sure he stays alive. Given his uses in debuffing and killing models below, you’ll find that Tartarus needs to position very carefully on the board to both remain safe and yet not be relegated to uselessness because he is too far from the action. Stealth will go some way to helping with this, but often any extra protection you can get is only making life more difficult for your opponent… Aiming to be in melee (target in melee penalty, especially for shooting that ignores Stealth) and finding Cover/Concealment are often crucial, providing you don’t compromise your board position to get them. Like the last remaining Bile Thrall, remember that Tartarus is always a threat in your opponent’s mind, so anything you can do to keep him safe will often pay back double later in the game when you can thresher up some new Banes and get you back in the attrition fight.
• Debuffing targets for Banes – Aside from trying to stay alive, Tartarus next focuses on applying debuffs to key models. Most often he focuses on using Curse, extending threat ranges + helping with melee accuracy for the other Banes. Considering the desire to keep him alive, often Tartarus can go first, just moving to a safe spot and applying the curse from there, then activating the Banes and moving around him into melee with the opponent. Ideally then, this will block off approaches to Tartarus as well, making melee difficult and making close range shooting (to ignore Stealth) without being engaged far from easy either.
• Blending infantry – If Tartarus can generally keep himself safe and reach a juicy target, looking for opportunistic Threshers is a great way to get a lot of use out of him. In this role, Tartarus is fantastic as a counter attack, waiting for infantry to approach his threat range before rushing out to kill them all. As always, try to go first where possible with this move, as not only can you avoid accidentally threshering your own Banes, but any newly created ones can activate with the rest of the squad, of course benefitting from the debuffs that Tartarus can apply (Dark Shroud + Curse, assuming it is on the same target). This is often a particularly destructive move, due to the fact that his high stats make it reliable and buy you a solid attrition swing, but one that can often cost Tartarus his life in retaliation.
• Bringing down heavies, Gargossals and Casters – With decent MAT, POW and both Curse/Dark Shroud to help others with the same, Tartarus can put a solid dent into a number of harder targets, all while setting them up to be more easily destroyed by other elements in your army. This can be particularly effective vs. casters, because they often cluster around other support models to turn into other Banes, usually assuring their destruction when the newly created models activate against their Cursed/Dark Shrouded target…
• Swinging scenarios – With a decent speed, pathfinder, stealth, and the ability to thresher models out of zones or off objectives, Tartarus is an excellent model for scenario play, loving the models that group up around key areas of the board and making it easier to catch models that might otherwise avoid him.  In retaliation, Tartarus is much more difficult to shift, moving easily through terrain (which can bump his DEF up to ugly levels), packing Stealth to avoid shooting and with high ARM/boxes to take the odd hit or blast that might otherwise take out contesting models.
• Running to jam – If nothing else, Tartarus can be fantastic in jamming up opponents, locking down a few models with his 14” running to engage move and being durable enough to avoid being killed by some of the more pillowfisted solos or troopers that generally hate being bogged down in melee combat. Eiryss and Gorman are prime contenders, but really any shooting unit with poor melee abilities will often be worth shutting down for at least a turn, forcing the opponents other models to come to the rescue and hopefully drawing them from other areas of the board.

As you can see then, Tartarus usually plays a mixed role in a given game, striking a balance between helping out your other models (usually Banes) and adding a good dose of personal destruction. Given how often and how thoroughly opponents try to kill him though, it is often worth going the extra mile to keep him safe, avoiding overextending him in favor of presenting a solid threat that only gets more dangerous the longer he is left alive. Tartarus is decently durable, but not in proportion to how badly opponents want to kill him, so I would say the hardest balance to strike with him is getting the most out of his many (ridiculously good) abilities without getting him exposed.

Casters:

So what casters can benefit from taking Tartarus? Looking at the above, we can see that Tartarus is both cheap and generally good enough to go in nearly any list without too much support, but there are a few considerations to get the most mileage out of him:

• A list with Banes – It might seem obvious enough, but while Tartarus is definitely a very solid combat solo, you really get much better use out of him when bringing Banes along, especially as 2 of his main abilities rely on them being around (Curse + Death Toll). It isn’t so much that he can’t work without them in the list, but more that if you are paying the points to have him in the list, you might as well get them as well. Of course not every list with Banes has to have him in (some casters will manage this better than others) and indeed character restrictions can prevent this anyway, but he is definitely worth strongly considering if you’re taking them.
• Needs the support for any Banes taken – Following on from the above, some casters really cannot help Banes with any of their main problems, such as enhancing threat ranges or overcoming their average MAT.  Tartarus fixes these problems nicely, so it isn’t so much about what the casters do for him here, but rather more whether he helps those casters get better mileage from their army. Generally then, if the casters lack ways to lower DEF, he will be a stronger inclusion in a list vs. those who can, but this is a bit of an oversimplification. Even those casters that can offer DEF debuffs or improve threat ranges might want to consider him anyway, as it makes the unit more self reliant and can frequently save focus for other jobs, making a more efficient list. Finally, any caster that focuses on attrition will greatly appreciate having him around, because any time you can remove opposing models and gather more of your own is definitely going to help support the rest of the army in grinding down the enemy.
• Can increase his damage output – Tartarus rarely needs any help given his solid MAT or POW, but obviously anything that ups these destructive capabilities further is only going to make things easier and reduce the odds of failure, which is important when sending your important solo on the attack. Anything that can increase his threat range or hamper retaliation is an excellent consideration here, especially when looking at some of the stronger Cryx denial feats that can often save Tartarus from retaliation and get him another solid turn of dealing damage.

Unlike some of my other spotlights focusing on Cryx heavies, Tartarus can fit into just about any list, because nearly any list in Cryx will appreciate having Banes around to crack open harder targets, making them even better and more self sufficient with his inclusion. With that being said, here is a list of some more specific caster synergies.

• Asphyxious1 –Breath of Corruption is generally pretty great for screening him, as keeping any infantry from chopping him up in melee while Tartarus sits in the cloud and eats the lowly single point of damage is pretty excellent for area denial. Both Parasite and Scything Touch (ST tends to be on another unit though) can be excellent for upping the damage potential to the point where even heavies can be threatened. Hellfire can synergize with Terror in forcing multiple command checks, but as mentioned, this is fairly situational.  Finally, Tartarus is not in the pGaspy tier list, so no benefits there. Generally Tartarus is a pretty solid choice in the list when including Banes, but be wary in that he is the only MAT buff they will have access to, making protecting him even more important.
• Asphyxious2 – Like pGaspy, Parasite benefits Tartarus doing damage, and Caustic Mist can mimic Breath of Corruption in doing wonders to keep him alive while being even easier to apply. Between Death Knell and Tartarus threshering opponents, you can happily mow through softer targets, so really these two have very little that they can’t handle. Sadly Death Toll does conflict with Daemortus picking up extra souls, nor can eGaspy return Tartarus with the feat so this can be a little annoying if he is taken off the board.  In the tier list, Tartarus gets a small benefit through redeployment, which can be nice if you spot a key opposing unit across from him you want to kill or avoid. eGaspy and Tartarus go together like bread and butter, with eGaspy nearly always having Bane Knights for the feat (who will appreciate having Tartarus if he is still alive) and often running a second Bane unit while using screens of Caustic Mist to get safely up the board. All in all, Tartarus should nearly always be in an eGaspy list unless you have a good reason not to take him.
• Deneghra1 – As the resident “Queen of Debuffs”, pDeneghra makes almost anything good with a wide variety of spells and a crippling feat. Shadow Bind (her weapon) and Scourge makes hitting targets easier and hinders their escape, Parasite reduces ARM and Crippling Grasp/the Feat reduces most opposing stats to make enemies even easier for Tartarus to kill while keeping him safer from retaliation. Tartarus won’t need Ghost Walk which is nice for her, meaning one less thing she has to worry about, and he will definitely appreciate a good use of Influence to clear annoying blocking models or spread out further destruction among a unit he is threshering. Once again, Tartarus doesn’t appear in her tier list.  Again a very solid choice, but Denny can often get away without Tartarus if need be given her general ease at debuffing and often getting the first strike anyway with the feat.
• Deneghra2 – Like her prime incarnation, eDeneghra can debuff quite substantially to help Tartarus. Curse of Shadows helps him do damage and can allow for some interesting offensive moves by allowing him to pass through enemy models (with no free strikes, though he has Ghostly anyway) before cursing or setting up an ideal thresher. Similarly, Marked for Death provides a defense debuff, and allows for some interesting charges or attacks on otherwise untouchable models (removing Incorporeal) or those out of LOS. What Tartarus particularly appreciates though is the judicious use of eDenny’s movement abilities (like Hellmouth, Seduction or Eclipse) and movement denial (the feat) to position models perfectly, enabling even better Curse/Thresher opportunities while avoiding retaliation in return. Her tier list regrettably doesn’t allow Tartarus (even though featuring near mandatory Knights).  Again, like pDeneghra, eDenny definitely appreciates everything that Tartarus brings to the table, but if you need him for another list, she is strong enough to do without.
• Goreshade1 –The most obvious reason for taking Tartarus is pGoreshade’s feat, and even if you don’t have any banes in the main list, there are bound to be some on the board that will appreciate his help. Most of Goreshade’s other spells feature around jack support, but he certainly can do very well in spamming stealth to further the denial that Tartarus can bring, as well as sharing around the Dark Shroud so Tartarus doesn’t have to.  The Deathwalker’s DEF and STR debuffs might help him hit or stay alive, even if it does require her to be rather close. Hex blast can remove crucial upkeeps and Mage Blight can also keep opposing spells away, so all these elements can combine pretty well in making Tartarus harder to remove. With pGoreshade’s tier, Tartarus gets a bonus move and extra opportunities to go first, really helping to emphasize the alpha strike as well as running in a list that is very good at spamming Stealth in keeping him alive. As always, a solid choice, particularly as pGoreshade will always have Banes and could always use the extra support in running them.
• Goreshade2 – Like his prime incarnation, Hex Blast and his Arcane Consumption continue the hatred of spells and upkeeps to keep Tartarus safe while Stealth (Occultation) is nice to further the mass Stealth models in the army and further spread denial, even if Tartarus doesn’t need the spell himself. As with eDeneghra, Curse of Shadows is excellent for maxing out the damage of his weapon or going for further hidden targets behind enemy lines. Sudden Death usually doesn’t see much use, but as a pseudo counter charge option, it can at least be ok if Tartarus gets into a better position or makes that crucial kill.  Finally, eGoreshade’s tier list gives out free upkeeps, possibly being useful for an early game Sudden Death (unlikely), but otherwise, it is just nice to have Tartarus in the list. With so many Banes on the table and the importance of helping them hit/charge further to make even more, Tartarus should almost always be included for playing a key role in enabling the eGoreshade playstyle.
• Mortenebra – Only seeing use outside of her tier list, Tartarus gets very little benefit from any of her spells. Doom Spiral and Void Gate can be nice to set up prior damage on warcasters while damaging/shutting down jacks or protecting him from beasts, but given that Mortenebra rarely spends focus slinging spells, rarely does this come up. Her other spells do pretty much nothing for him. With that being said, Tartarus can make a very solid inclusion in the list when running Banes, as they otherwise get little support, and this helps keep them a very effective independent fighting element. The biggest benefit Tartarus gets by far though is her feat, helping pull off even more destructive threshers, and aiding the Banes, he should be supporting to do the same. Generally then, Tartarus does more for Mortenebra than she does for him, bringing the versatility of a powerful infantry unit to her list without the need for any support in doing so. If you need him in the other list though, Morty can certainly do without, particularly as she tends towards running in tier.
• Skarre1 – Along with the rest of the army, Dark Guidance helps Tartarus hit in melee, occasionally reducing the need for Curse or simply helping bring down things with really high DEF. As always, pSkarre’s feat can improve Tartarus in both hitting power and survivability, really helping him with causing added hurt to harder targets and hopefully keeping him alive for another turn.  Blood Rain and Hellfire are situational, being nice for clearing space or forcing extra terror checks, but generally, they will only be used sparingly in conjunction with a Sacrifical Strike accompanying Bane on the assassination.  Backlash is also a nice ability here, particularly in conjunction with her Great Rack (knockdown), but again this rarely has much to do with Tartarus directly even if he assists in pulling off the win.  Tartarus isn’t present in either of pSkarre’s tier lists, and she can certainly do fine without him like the Deneghras if he is needed elsewhere, but is otherwise an ok choice with any infantry swarm that plans on bringing Banes.
• Skarre2 – As with Mortenebra, a lot of her abilities don’t do anything for Tartarus (Admonition, Perdition, Seas of Fate) or are likely to be elsewhere (Death Ward). As with pSkarre, he still benefits indirectly from Backlash on an assassination and the Great Rack/Blood Rain even if they are a little situational. Black Spot, however, is a different story altogether, helping him and any Banes massively with their accuracy, damage output and often making retaliation difficult due to the large volume of attacks. Her feat is also particularly strong on Tartarus, causing an inevitable tide of complaints when Tartarus likely skirts the edges of death and gets into the perfect position for the following turn. Again her tier list prevents you from taking Tartarus, but as with her prime incarnation, he is otherwise a solid choice in a normal list when bringing Banes.  If anything, this can be even more important under her epic version, as eSkarre can often struggle with cracking higher ARM and typically needs fairly independent units when running a more battlegroup oriented list.
• Terminus –Terminus generally doesn’t do much for Tartarus outside of Tough, but Tartarus certainly does a lot for him in helping the Banes he wants to run more efficiently and clearing key lanes for the rest of the list to advance. Tartarus does get the benefit of Maledition which can be nice (although be careful with the Threshers), and likewise, Terminus appreciates the Dark Shroud in return, so they can complement each other nicely in melee, triggering even more terror checks. Again Tartarus doesn’t make the tier list, but otherwise will be a strong inclusion in a Terminus list for boosting his favorite unit of Banes. As an ideal Sac Pawn unit and being able to break the few things that can threaten him, Banes are a very strong choice in any Terminus list, so Tartarus will often make it by extension when Terminus only offers them minimal support.
• Venethrax – Venethrax in many ways can play similarly to Terminus above. Soul harvester doesn’t work with Death Toll but can certainly yield a few extra souls when strapped to an accompanying unit of Banes. Venethrax’s feat can help block LOS to Tartarus in much the same way as eGaspy’s clouds above, but this can be a bit unreliable with positioning and also presents an anti-synergy with Death Toll in having mutually exclusive triggers. Lamentation also gives him an element of spell protection, which combines nicely with the shooting denial of his Stealth/feat to make him even trickier to destroy. As above, Blood Rain and Hellfire are nice to get Tartarus out of a spot of trouble and force more terror checks, but these will generally be situational at best.  Again, Tartarus doesn’t make the tier list, but generally, Venethrax will benefit from Tartarus though in much the same way as Terminus above; supporting units in ways that he otherwise cannot manage and cracking the few things that can kill him in return.
• Witch Coven of Gharlghast – Like with eDeneghra, Curse of Shadows can up the damage done whilst Tartarus definitely loves moving deeper into melee through opposing models to get some opportunistic threshers. While Tartarus doesn’t need Occultation (Stealth) or Ghost Walk, it is nice to have a model that needs even less of their support, and he definitely appreciates the Feat or Veil to screen him and keep him surviving for that much longer. Finally, Stygian Abyss can provide a great (if unreliable) debuff in preventing movement and lowering defense on a critical hit, make it easier to land that crucial hit on more evasive opponents (assuming they survive) or preventing them from catching Tartarus in return. Tartarus doesn’t appear in either tier list, but otherwise, it is generally a pretty decent choice for improving any Banes you might have if he isn’t needed elsewhere.
• Scaverous – Ghost Walk isn’t needed for Tartarus, and although Scaverous has Death Ward, it will generally be needed on something else.  Despite this, Tartarus does appreciate both Icy Grip and Feast of Worms though to up melee accuracy and damage potential, enabling a stack with his own debuffs for particularly troublesome targets or for him to put his abilities to use elsewhere.  Telekinesis is a particularly fantastic spell for Tartarus for many reasons, getting him into ideal charges lanes, clustering up opponents, getting the backstrike bonus or keeping key opposing models from retaliating very effectively.  Again Tartarus doesn’t make the tier list (I swear they all forgot his party invite in the fluff!), but he is usually a solid choice when running Banes, even if he isn’t mandatory with the other spell support options in the list in helping them instead.
• Asphyxious3 – Carnage helps with melee accuracy a lot, but as with Dark Guidance, Tartarus is still a great option for the threat range and in situations where Carnage is not available or out of range. Hex Blast can strip important upkeeps, and his other offensive spell, Bone Shaker, can clear space on the board to set up a better charge lane or thresher. Otherwise, his other spells do little for him, with Mobility having no effect and both Ashen Veil and Scything Touch being helpful for DEF/damage but usually seeing use elsewhere. As with the other casters that camp really well (Scaverous, Venethrax, Terminus), Tartarus will often still be a strong inclusion for running Banes, helping maximize their impact on the table and cracking open the few hard targets that can effectively assassinate in return.  Again, no tier list options here.
• Sturgis – So my experiences here are very limited, and the model has yet to be released, but some things immediately come to mind. As with the other casters, Occultation will have better targets, and Blood Rain is pretty situational on the whole. Aside from Parasite upping damage, one thing that I think really stands out here is Sturgis’ feat, dragging models into ideal positions and making key long range charges (Curse) or Threshers even easier or more deadly than before. On the whole though there isn’t a lot of synergy, but as a relatively powerful independent unit, Tartarus (with Banes) will probably make a strong inclusion providing he isn’t needed more within the other list.

Other Synergies:

There are plenty of other ways that Tartarus can help/be helped by your list, but here are some key examples:

• Jacks – The Desecrator stands out from the start for picking up free focus from him, but of course, anything that can slam/push things to reposition opposing models only makes things easier for Tartarus to do his job. Most jacks will in return definitely appreciate the Dark Shroud, helping make up for the fact that many of them can struggle with hitting power while taking on harder targets. Other jacks of note include the Ripjaws (Vice Lock -2 DEF, prevent movement), Stalkers (Grievous wounds to prevent tough/healing), Seether/DJ (more Terror/Abomination checks) and Reaper/Malice (Drag). On the flipside though, try to stay away from jacks that are hungry for souls, as Death Toll prevents them being gathered and fighting over who gets what can become quickly inefficient.
• Units – Banes of all sorts are the obvious standouts here, with Knights and Thralls synergizing directly with his many abilities (especially Curse/Death Toll) and likely being an auto-include in any list that has Tartarus around. Even Bane Riders might occasionally appreciate the Curse, helping them if the leader would be out of range or getting the extra threat for the entire unit before the charge. Other choices of note include Bile Thralls (clearing space, and Tartarus can often survive the hit if need be), Black Ogrun (More Drag, further terror checks), Blood Witches (positioning for Entropic Force and Dispel on a key model, clouds for further denial, Incorporeal to prevent getting in the way), Blackbanes (Incorporeal again, and fire when applicable), and the Withershadow Combine (Puppet Strings, Unbinding for removing upkeeps). Again, watch for things that need souls/corpses, such as Soulhunters or Necrosurgeons that will compete with Death Toll in losing out one of the abilities.
• Solos – Machine Wraith (possession of key jacks after beating or for scaring them away), Pistol Wraiths (preventing enemy movement/actions, keeps Tartarus safer from retaliation), Raider Captain (Critical Knockdown), Warwitch Siren (Shadow Bind to debuff or prevent movement, Seduction to further force opponents models, Venom to clear up space), Darragh (Death Ride to keep models out of the way, Beyond Death for survival, Hellfire for more Terror), Gerlak (more terror) Gorman (Further debuffs…), Madelyn (extra positioning for other models to get out the way), and Saxon (Take Down to ignore tough, keep nearby to harass beasts).

And there are many more!

Conclusion: 

In summary then, Tartarus is a particularly powerful solo model, but remember that this makes him often a priority target for all opponents. Knowing what can kill him and making opponents work to do so is definitely a main priority when putting Tartarus on the field, as this will often draw out many opposing models through over-extension as they work to put him down. Generally, then, Tartarus is a very solid choice if you can learn to protect him while getting the most out of his Curse/combat abilities, so getting this balance right will be a fundamental skill when including him in any list. I would say that any time you include Banes in a list Tartarus is definitely a very solid consideration, but if this isn’t always possible (Character restrictions, points), then Banes can often manage ok without him, particularly when paired with a caster that can help with hitting or deliver them across the table.