Chaostic
Just in case you need an idea for a truly difficult place/mission, here's an idea. Though I'm 100% sure he'll get the job done eventually, but doesn't mean this man couldn't use some extra help to actually save people. I mean, this ... MAN has been scouring the umbral planes since forever, he has no problem making demons taste the bite of his sword. Actually saving lives though... yeah, he's not so great at that. I mean, technically he is, but not really. It can be interesting, just have the intro mission for this man be the 'hero team' simply has to wake him up from the tomb and afterwards, well, just let DOOM take over at that point.