Hard for me to say. I know a few people have mentioned nilomoth is pretty good. Others May say its up to. Hopefully someone els gives some opinion here as well.
I vote for nilomoth because he has the ability risky heal and I love that ability.
And on top of that you have a S rank one so you could possibly heal your whole line up with bonus actions if he doesn’t die
I think I will go for Nilomoth. It can only hit single targets but I have quite a high chance for bonus actions so I may be able to hit often hard.
Plus it’s abbilty to heal himself and other memeber might be usefull.