This DLC is absolutely amazing. Might even be better than the base game.
That being said, Jori is killing me. I can't barely get him down to 50%. Using my mimic tear of course. Without giving too much info on my build, most bosses so far haven't been bad. Renalla was hardest so far but only took 5-10 tries. I want this last map and must get through Jori to get it.
I just beat this guy. Walked in with a colossal hammer and pancaked him. Took two tries because the first time I didn't realize he didn't turn into the fat one, but it was a summon instead.
I don't really have much advice, really. Run sideways towards him when he spams projectiles, dodge into the big projectile, ignore his summons since your big hammer will hit them too anyway.