It's pretty awesome to see Lorem like this as it really helps put the pieces together between how other demons were, how they and humans viewed her and who she actually was.
@hayatekanzaki
Zeke's ability isn't compatible with cooperating with other demons (hence why he'll get along with Lorem, they're both pretty lonely, although Lorem is less lonely since she does have her sister - same with Chiharu). If he was participating in the fight, he would be preventing them from being able to use their abilities.
Also, considering Lorem's heat is known to be able to vaporize his poison, the moment Lorem finds out he's present and what his ability is, he won't have a chance. So I would say that the plan is that he's their last resort - he jumps her when she thinks the battle is over/when she least expects it, and once her demonization and ability are sealed then it'll be a more even fight.
Honestly though, Lorem is so powerful; not only are her ability and demonization far above the norm, her battle instincts are incredibly sharpened. To be fair, unlike most demons, she has come back from near death situations many times thanks to her sister's ability, so she's accumulated battle experience in a way that would be very difficult to replicate for anyone else as they would long have died before reaching her proficiency.