“No one ever looked for a girl,” he said. “… The error crept in from the translation. Dragons are neither male nor female, Barth saw the truth of that, but now one and now the other, as changeable as flame. The language misled us all for a thousand years. Daenerys is the one, born amidst salt and smoke. The dragons prove it.” Just talking of her seemed to make him stronger. “I must go to her. I must. Would that I was even ten years younger.”

The Great Sept of Baelor

“You must. Must tell them.”
“Tell them what, my lord?” Sam asked politely.
“All. The Fist. The wildlings. Dragonglass. This. All.” His breathing was very shallow now, his voice a whisper. “Tell my son. Jorah. Tell him, take the black. My wish. Dying wish.”
” Wish? ” The raven cocked its head, beady black eyes shining. ” Corn? the bird asked.
“No corn,” said Mormont feebly. “Tell Jorah. Forgive him. My son. Please. Go.”

Unsullied! You have been slaves all your life. Today you are free. Any man who wishes to leave may leave, and no one will harm him. I give you my word.

Will you fight for me? As free men?

There is a reason. A dragon is no slave.

A dragon is not a slave.

Game of Thrones 3.04 - And Now His Watch is Ended
I have no doubt the revenge you want will be yours in time…if you have the stomach for it.