The Old Ones of Hogwarts

The story begins.
Ian thought he was just a little wizard with a bit of talent (a cheat code) who could become stronger with hard work.
however.
As the story unfolds...
He gradually began to discover.
The teachers who had been learning magic from him were either once-famous and powerful figures or characters mentioned in various legendary stories.
"Standing before you is a noble apostle of the Enchanted Realm, the common spokesperson for the departed, and the heir designated by the founder of Hogwarts!"
"What? The noseless monster's trying to cause trouble? He must not have heard of my original spell, which is recorded on the Chocolate Frog's celebrity collection cards!"
"Dumbledore's Summoning Curse!"
"Dumbledore's Berserk Charm!"
Ian chanted the incantation for "Touch God's Protection".
Suddenly, silvery-white threads surged and converged, coalescing into the figure that had haunted a certain professor with guilt for his entire life, blocking his way.