Osrin's magic has always been that of a fey prince: one willing and able to reward his allies, compel the weak through fear or charm and burn anyone else who would stand against him. As his magic has grown stronger, this aspect has begun to show itself more in the waking world in ways both subtle and overt. His horns have grown, his eyes have changed and he smells faintly of fragrant smoke when excited or angry.

When his magic runs wild or he calls on his greatest powers, the glamour cloaks him completely with a regal outfit and bearing to match.

(Mechanically, he's a Glamour Bard and looks like this when he uses Mantle of Inspiration, Mantle of Majesty, Dream or Yolandae's Regal Presence.)

A character sheet done by pomidaea, who went above and beyond working with me on the clothing and other details.
You can find her at https://pomidaea.carrd.co/