Greetings all!

My necromancer is collecting impressive "followers" and I wanted to know what is the most powerful magic-using only NPC character type that I can defeat and reanimate? So far I've found the Arch Necromancer who is level 46. Generic characters ideas and named characters are welcome.

http://elderscrolls.wikia.com/wiki/Orchendor

Orchendor is reputed to be one of the best dead thralls. He keeps his teleport ability, it seems.
I've never tried him though, I usually run around with a frost atronach or two by my side.

Awesome, thanks for replying. I've never done Peryite's quest so I have never encountered him before. Looks like he would be great but I hope he doesn't aggro my other followers with his destruction spells. I had that happen using The Caller because she kept hitting Ahtar with fireballs.

Wow I also just discovered that the Volkihar Master Vampre (level 53) IS NOT the most powerful vampire I can have following me. Looks like I need to go out and find a Nightlord Vampire (Level 60), or preferably a Nightmaster Vampire (Level 65). Of course my necromancer is only Level 44 so I might not even be able to reanimate them.

Orchendor (as mentioned) is pretty good. Kornalus moans like a banshee, but is beastly with magic attacks. Malkoran retains his Shade ability and is also beastly. The Volkihar Vampires are about the highest level thralls you can get (with necromage perk).

Highest level thralls for us Console users is lvl 40. with the exception of boosting up the level cap with the necromage perk. Necromage perk grants 25% bonus against undead. This applies to the level cap for dead thralls created out of undead, too! Normal level cap is 40, with necromage this gives 40 x 1.25 = 50. So Volkihar Vampire at lvl 48 is the highest level dead thrall possible on the console. afik. This only applies to vampires, since they are undead. It doesn't increase the level cap for non-undead thralls.

I'm on PC and using Skyrim Redone which adds 3 phases to the Necromage perk .... so I'll be reanimating the heck out of some high level baddies.

*I wish there was a way to turn off the moan for any reanimated thrall.