Originally Posted by
Thontor
Medivh doesn't have the same backstory in the movieverse. I got the audio book of the Durotan prequel novel. It also included the first chapter of the Warcraft movie novelization
In it, Medivh, as an 11 year old boy, enters the Chamber of Air in Dalaran. Appearing before the Kirin Tor council. Arch-mage Antonidas tests him with some questions and answers.
"There is a theory that every star in the sky is a world. And that each of these worlds is alive with beings of it's own. What says our novice to this concept?"
"No world can equal Azeroth. The beauty of Azeroth, its vitality and abundance are unique" Medivh ansers
"Who can be trusted to care for such a treasure"
"One who can master the forces of magic to keep our world safe. The Guardian"
"I see. All the forces?" Antonidas asks.
"No. The dark forces are forbidden. The dark forces are the mirror of corruption. The dark forces turn the user back against his own intentions."
"And what do we learn from this?"
"That magic is dangerous, and must be kept from those without instruction. No race of men, no dwarf, gnome, or elf. None but the Kirin Tor must use magic."
That's apparently the first part of some kind of test...
Antonidas continues:
"We sense your power, Medivh. We admire your focus. Your appetite for knowledge. We probe and test it as best we can, but sadly the most important question is one that cannot be answered until it is too late. The life of a guardian demands sacrifice that you cannot begin to understand. Yet, we ask you now as a boy to bind yourself forever to the wheel of this vocation. Are you willing to prepare yourself in all ways for the day you will become the master of the tower of Karazhan?"
"I am" answers Medivh
"Then prove yourself!"
Then some magic creature of shadow appears, Medivh realizes it's not real... finds the mage who's "creating it" and uses a spell to silence him.
"Not what I had expected, but effective" Antonidas says.
Then a hole in the floor opens by Medivh. It is filled with a pool of bubblying water, a white flame burning within its depths. Antonidas moves to stand beside him.
"Give me your hand Medivh" Antonidas says. Medivh obeys.
"The day will come when you will be called to serve. The oath you pledge is forged in light. No mage shall be your peer. None your master. Your responsibility will be absolute."
Medivh moves closer to the flame. It then snakes outward and wraps around his arm and sears a pattern onto his skin. The Eye of the Kirin Tor.
Now the council all are bowing their heads to Medivh in a gesture of acceptance and respect.
"No mage shall be your peer, none your master. Guardian" says Antonidas
This appears to be the vows and initiation of a new Guardian. The thing I find interesting is that in the Khadgar character video, we see him with a Eye of the Kirin Tor on his arm. Did he go through the same initiation as Medivh to become the next guardian? Was it because Medivh had renounced his vows? And now in that clip, Khadgar says he renounces his vows... so many questions...