Who said "I have learned that even the mightiest must adapt."?

This quote is attributed to Drogon.

I have learned that even the mightiest must adapt. - Drogon

"I have learned that even the mightiest must adapt."

Drogon Change

"I am fire. I am death."

"Dracarys."

"A dragon is not a slave."

"I will burn them all."

"Change brings new opportunities."

"Every day is a new opportunity."

"Healing doesn't mean forgetting."

"You either get better or you get bitter."