Who said "A soldier's duty is to obey."?

This quote is attributed to Grey Worm.

A soldier's duty is to obey. - Grey Worm

"A soldier's duty is to obey."

Grey Worm Leadership

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

"Unsullied do not fear death."

"We are the dragons' soldiers."

"We serve the Dragon Queen."

"A leader must be fair and just."

"Integrity is everything."

"One must take responsibility for one's environment."

"In this house, I make the decisions"