Easier End Game
I was getting tired of taking screenshots of every level to find my way back out. Turns out I didn’t need to. Yeenoghu was quite willing to follow me, so I took him on a 39 level tour of the dungeon and killed him on level 1. Walking back through the levels I'd already revealed, even with a demon lord in tow, was much easier than facing the changed levels you get after killing your nemesis.
This run also showed me why disintegration resistance matters. I’d always figured it was pretty much useless, but I’d apparently never hit the mid-game without reflection before. Around level 25 a group of yellow dragons destroyed my main weapon, my cloak, and my bag of holding with all my goodies inside before I could make a hasty retreat. Re-equipping cost me 2-3 hours of scrounging and crafting.
Lastly, it’s the first time I’ve made it out with my original pet. Though that did take saving the body and a well-timed raise dead spell right at the end.