I suppose the only person Mentathiel did not get on with was Berric. They just had such diametrically-opposed views despite sharing the same nominal alignment and half a skill-set. Berric was quiet, thoughtful and yet implacable when he set his mind to killing where Mentathiel was outgoing and willing to kill only when things went wrong. Mentathiel just couldn’t get comfortable with his single-mindedness and lack of moral flexibility, a trait we will see again later.
Unlike the ranger, Ulric has cracked jokes. Ulric has probably even smiled under that (creepy) mask. Ulric knows how to complement her skills and they work as an effective pair in combat which quickly leaves gently-twitching corpses and a lot of blood. She’s never going to have an in-depth conversation with him, never going to debate the finer points of poetry, but he’s got her back and she’s got his.
As far as Mentathiel is concerned, Gracus is a problem. He’s not a bad person, not a danger to her, not even someone she dislikes. They’ve pulled each other’s backsides out of the fire (perhaps he’s done it more, but who’s counting?) and fought back to back, but their moral codes don’t ever seem to mesh that well. It’s not just about Jarahmeel, it’s about how comfortable he is with killing too and about necessary evils and the general sense that any plan she concocts with Arith includes the same caveat; don’t tell the cleric…
Finally, Arith… Oh, the tomes she could write about that boy… And there’s part of the problem. She sees him as a boy, not a man. He’s trying too hard to be some kind of arch-wizard in her mind and that leaves him trying to be too firm and dour. Yeah, he’s seen some awful things, but so have they all. He’s also morally compromised and not in the way she’s comfortable with. It’s a shame, because she does kind of like him; he’s the only one in the party near to her age (though not being human, she’s kind of older and younger than him at the same time) and that probably makes a difference. There’s nothing romantic there, but I think she kind of wishes she knew how to fix him. She found her equilibrium, so there’s some hope that he will find his somehow, but there’s also the chance that she can’t save him and will end up having to stop him instead.