About difficulty trophies

[bladesoframen]

I've been wondering about this for a while now, and @Mesopithecus confirmed it. You only need to beat the final boss on the required difficulty to get the difficulty trophies. This doesn't change the fact that you need to beat the game 3 times to unlock Hell difficulty, but if you load your devil game before the final boss, you can beat the boss on Hell, and get the God Crest Trophy.

 

What this means, is that you can run the game even faster through the lower difficulties (as if new game+ wasn't easy enough), and get the plat in 3 playthroughs. (and post game content and what not). If you're looking to run the game really fast, I recommend getting the 30k kill grind out of the way asap (like Blue Tower), giving you early access to god parts, allowing you to breeze through the game.

[Mesopithecus]

Skipping that extra play through saved some of my sanity, so thank you @bladesoframen for recommending I try it.

 

For my Devil playthrough, I cleared practically all of the final dungeon by lowering the game difficulty to Normal then just raising the difficulty back up to Devil before the final boss.  I went back to the inn and saved before the final boss on Devil, beat the boss and saved in a new save slot.  Then I loaded up my precious Devil save that I made before the final boss, increased the difficulty to Hell (which I'd just unlocked) and beat the boss again to unlock the Hell trophy.