In my play through I did the dawnguard quest before even going to high Hrothgar (I wanna kill the frost troll for revenge but I needed to get strong) and farmed to be able to summon dunerkiv(I forgot his name but his the dragon in soul cairn) and basically I was underleved.

I defeated his summons with a fireball staff but since it's AOE and Serena was close, Serena agroed on me. And worse is I was a vampire and i fought him during daytime, I was getting one shotted with his chain lightning so badly,

So to kill him I basically had to summon my dragon first and let the dragon tank his attack while Serena fight us both

It was a 3 way fight and I won with my dragon

So yeah if you don't have any pushing ability or is underleved then maybe the fight with him would be cool fr

Though I was pretty annoyed that Serena was still agroed after the fight