Thunder god TG

In a world were mana appeared and transformed animals into beasts, humans start to use mana to fight back the fighters are called Hunters. Three colleges were made to form new Hunters, blacksmiths and alchemists, their names are :
-The north’s Kraken’s depths which specializes in ice, water and defense.
-The east’s Roc’s nest that train in the air, speed and flexibility.
-The west’s Dragon’s gate that was created by one of the original Hunters where they train fire magic and strength.
Sam is a normal kid until his talent is tested to be an S grade talent... but he is compatible with Thunder. Will he make it without a teacher to guide him ?