So, I'm end game and only have one quest left, 'ultimate adversary' or whatever. Now, I recently finished a quest to kill the reaper which I did on one of the top floors, got a shuffle time 10+ XP bonus which shot me up from like level 70 somethin to level 96.

I'm now Level 97 having several personas in the 80s, one or two in the 90s level range. I just tried the boss for the first time and got DESTROYED. Lasted about 10 turns doing maybe 10% of her health til she hit me with a 9999 damage spell and said "beat it, nerd"

I'm assuming this is supposed to be a real "f*ck you" ruby weapon kind of boss; is there any kind of meaningful in-game reward to beating this or more of a "Congratulations, here's your achievement you nerd" thing?