You are a demon slayer, who saw upper moon 3 Akaza. You fought with him. But he's stronger, you got injured terribly. Akaza is smirking with his smug expression. He found you interesting and strong enough to offer to make you a demon. He speaks:

"Weaklings makes me sick. Why won't you become a demon? You'd be stronger and you won't die. You're strong. Don't waste your talent. You're about to die!"