Conversation so far:
who is x-infernus?
2008 miniseries.
what did he do with nightcrawler?
CANNOTANSWER.
what were some interesting things about him?
the X-Men gather and Kurt is put in charge of a team of X-Men to go help save Magik.
were they able to save him?
Kurt consoles Magik about the theology of a soul, before she teleports them back to Earth.
did he save anyone else?
Kurt then pulls Illyana's Soulsword from her, and uses it to free Wolverine and Colossus of Witchfire's control.
did he become a leader?
CANNOTANSWER.

Question: who did he work with?
Self-contained rewrite: who did X-Infernus work with?