Location And Name Of All The Master Trainers:

Acrobatics-You are told that the trainer's name is Aerin, but when you get there the only person there is a man named Tobern. Don't worry because Tobern is also a master trainer (no one in the game is named Aerin). The camps location is in the northeast, in the northern foothills of the Vallus range.
Alchemy-The man's name is Sinderion and he will train in exchange for two bottles of wine. One Tamika
and one Surlie Brothers both from the year 399. This may be hard to do as there are only 30 of each in the entire game. You can find one of each in the castle Skingrad cellar (two-tumbler lock). His location is the basement of the West Weald Inn in Skingrad.
Alteration-The Argonian's name is Tooth-in-the-Sea.