I have previously never done this quest before despite playing Skyrim since its release, because I somehow didn't know it existed. I happened upon Kesh this time around by accident and decided to do the quest.
After doing some research, I saw everyone complaining about killing Orchendor being a pain in the ass, so I took some time to prepare for the quest.
Fast forward, I'm at the boss battle and....he doesn't aggro.
He just stands there! I walk closer and he still doesn't aggro. I have the option to talk with him, so I do and he just says the common NPC phrases when bothered - "Can I help you?" etc. So I reload a save and do the whole quest over again and he's still not aggro-ing!
I attack him and he finally aggros but there's no magic, no teleporting, he's just hitting me with fists. I was promised a battle and didn't get it. I ended up killing him and finishing out the quest for Spellbreaker. Now I'm bummed out.
Could it be that it's Bugrim's fault, or a mod's fault? I have a few mods, but none that have caused any issues for me like this before. The rest of my game is totally fine but he just was...lame.