So I guess... *Spoilers*, for anyone that hasn't done the mage college quests.

In the "Staff of Magnus" quest I'm up to the Morokei boss... but I just cannot seem to beat him?

I'm a full mage, level 20, playing on expert.

I have fire destruction perks, conjuration perks and restoration... and a couple of points in archery that I regret, lol.

His lightning can 1 hit me, but usually leaves me with about 10 hp from a single shot.

I only have a fire atronach spell at the moment for summoning. But he just uses fury on it anyway so that's pretty useless.

I just have no idea how to beat him? Lydia can take a few hits from him. But I can't just stand there and heal her because the splash damage (chain lightning, or that fire wall thing) just kill me.

Any suggestions? Preferably that don't involve me leaving the dungeon.

I beat him when I was level 16 on my mage on master difficulty. Took about 20 reloads to finally kill him, the strategy I used is basically use Lydia is a meatshield, while healing her whenever she gets low, or every 15ish seconds, and spamming fireballs at the guy while I'm not healing her. I also hide behind the pillars to dodge his shock attack which 1 shots me, then I pop out and hit him with a fireball real quick right after he tries to shock me. I also summoned the fire atronach as much as I could. It's a long fight, mainly just hide from him, fireball him while lidya's tanking, heal lidya frequently, and use summons, and some mana potions.

I hid behind pillars while waiting for my mana to regen, then I stunlocked him with impact. Repeated this 5 or six times and he went down. Wasn't easy though, took about 15 reloads. He's tough.

I stayed outside the door and kept hitting him with Fireblast (If that's what its called :/) Also quick saved on every hit cause he can One hit you.

When you say you hid behind pillars, which ones? Because I have my save where I've already killed that mage that's beaming him on the lower level. Then I kill the one on the upper level, and he instantly attacks me.

He is one tough son of a [censored]!

OK, thanks guys I beat him! And then I reloaded and beat him two more times, just to make sure, lol.

Is he a bit glitchy? Sometimes he just stood there and did nothing. Or did he run out of magicka or something?

I don't think dragon priests run out of magicka, since I hit both the ones I fought with lightning spell after lightning spell while they spammed wards and spells, and they never ran out.

Maybe his AI just broke.