Tbh I originally made Riven as my go-to hyper oc but I love lore to much just to leave him like that.

Riven was raised as a lord of reasonably valuable lands, he was spoiled by his mother who taught him everything rightfully belonged to him and he was entitled to whatever he wanted. As an adult he basically ignores his duties as a ruler and studies magic using his family fortune to fund his obsession. In this world magic is very closely regulated because it was almost used up there are those born with magic and those that weren't, Riven was not but feels entitled to it. He has very little formal training with magic but money has closed the gap more or less. He meets Laun after inspecting his monthly purchase of magical sources and breaks the spell that was binding him in the stone then binds Laun to him and proceeds to use him.

Not having formal magic training it exerts stress on his body, his larger form is for larger more complex spells and serves as a 'heat sink'. He can preform magic in his smaller form but it's uncomfortable and wears him out more quickly.