Tolfdir is an elderly mage who resides in thhe College of Winterhold. He also provides the first few quest for the college. Tolfdir is a master level alteration trainer
Tolfdir sells leveled mage equipment including Staves and robes he also sells all the alteration spell tomes, obtainable once you reach their level
Tolfdir will give you a number of quests including:
Alteration Ritual Spell: Find the Fang and use it to get Heartscales from a dragon for Tolfdir.
Good Intentions: Find and consult the Augur of Dunlain.
Tolfdir the Absent-Minded: Help Tolfdir find his missing alembic.
Under Saarthal: Uncover the mysteries beneath this ancient ruin.