The Grand Duke of Owls was a powerful owl sorcerer who briefly fought in the Disney vs. Non-Disney Villains war against Dr. Facilier.
He was the main villain of the Don Bluth animated film Rock-a-Doodle.
Disney Vs Non Disney
Vs Facilier
Eris, seeing the Grand Duke of Owls as a threat to her plan, sent her minion Doctor Facilier to asassinate him. Facilier confronted the Duke in his tree. Rather the silently surrender, the Duke grew to enormous size, and created a tornado to try and kill Facilier. Unfortunately for him, Facilier managed to reverse the Duke's tornado into shrinking him to a smaller size. In this state, he is presumably killed by Facilier.