Who said "Knowledge of your enemy is half the battle."?

This quote is attributed to Grey Worm.

Knowledge of your enemy is half the battle. - Grey Worm

"Knowledge of your enemy is half the battle."

Grey Worm Knowledge

"I am Grey Worm. I have no name."

"Unsullied do not fear death."

"We are the dragons' soldiers."

"A soldier's duty is to obey."

"We're not just after treasure. We're preserving history."

"The mind is humanity's greatest tool."

"A tidy room reflects a tidy mind."

"You can learn a lot about a person by how they keep their space."