Lambach
Arcane
Again, in mission "Ruin draws near" I end up dying about 10 times to human boss spear faggot and killing the main Yokai boss Shibata Katsuie on first attempt.
Interesting, Shibata is probably among the Top 5 most difficult Bosses, not counting DLC ones. Though I think the size of the Boss Arena is a huge factor there. He'd probably be a good bit easier if you fought him in a large open space.