Finally took out the final boss, took me probably 6 hours of going at him non-stop, what a pain. I was really tempted to give up, I only got him to his final phase twice, and the second time I took him out. I'll have all achievements once I start the next journey, ended the game at level 151 at 72 hours, and at normal difficulty (bit of a misnomer there, it's hard af) and no summons. I'm missing a few phantom relics so I'll probably clean that up first, but looking forward to NG+!