What would be the best follower a Mage like me could have? I have a level 72 nord mage and I play on master difficulty, and I need something that'll keep the random encounters in check. Something strong, but melee, so I can spam the enemy with destruction spells and level up destruction on the go. I don't want the enemy killed too quick. I mainly use destruction (level 63) but I do rely heavily on conjuration (level 100) I have all the perks for conjuration, and decent thralls, but I need someone I don't have to CONSTANTLY resurrect. I currently have the dwarven sphere follower from the dragonborn dlc, and marcurio of riften as a follower, but he kills everything from a distance before I even see it.
You're probably best off with an essential follower like Mjoll the Lionness. She won't ever die, and she wears heavy armor so she'll tank hits for you. That said, if you don't have the Unofficial Skyrim Patch then J'zargo from the College of Winterhold will keep leveling with you since he doesn't have a cap, so he may end up with more health than even heavy armor class followers (as I recall, he has a thing for wearing armor too).
A full list can be found here: http://www.uesp.net/wiki/Skyrim:Followers, the page mentions that "Seven permanent followers are essential as well: Derkeethus (due to a bug), Mjoll, two Dark Brotherhood Initiates, Cicero, Serana and Frea are essential." As far as what you are looking for, Frea is also mainly focused on melee, although she uses Light Armor as well as Alteration and Restoration magic.