For parties interested in how the movie
Twins fares on the battlefields of the Iron Kingdoms, here's the
Searforge Blog. It contains mostly tactics and army building articles for the Searforge Contract, but it also has news when models are released. In this case, the news is spoilers for Lesser Warlock Brun Cragback and his character heavy warbeast Lug. Check it out.
My impressions of Brun and Lug are that they are faster than the Rhulic heavies and have All Terrain unless you like marshalling said heavies with Thor and don't use terrain. Also, for zero focus investment, they put out more damage against a single target than a focus-laden Driller with Strength of Granite depending on
ARM (Driller with SoG still wins against targets with really high
ARM). Their problems are the same as the Rhulic heavies in that they can't handle infantry very well, but because Brun is there to help out, they're actually a little better than the jacks.
When using them with Circle, only take them in larger battles so you don't have to sacrifice the Fury generators for your main warlock. Make sure you take your anti-infantry stuff elsewhere in the list. Krueger is a natural fit because he meets the first criterion, and his buffs don't discriminate by faction. Brun and Lug are harder hitting than any unbuffed warbeast Circle has access to, so these guys cover one of their weaknesses.
I confess I don't know much about Trollbloods, but the availability of Rush and the already considerable power of the Dire Troll Mauler (or Earthborn Dire Troll) makes Brun and Lug less desirable. Still, they might find some use with a Minion friendly warlock as they are much cheaper than the Axer and Dire Troll combo. Who are the Minion friendly Trollblood warlocks? Grim?
Since Brun is so hard to kill and Lug gets ticked off when Brun dies instead of running away like all of the other Lesser Warlock beasts, it's actually more prudent (and easier) to kill Lug first unless you have a way to stop Brun's free damage transfers. Models that Push as they attack help here.