Sage: "My parents aren't my biological parents; I come from a foster home."
mc: "Oh?"
Sage: "I only have vague memories of it, but I was rescued from a life I don't want to imagine, thanks to mom and dad."
Sage: "And look at me now..."
Sage: "I'm so fucking grateful for what they did."
Sage: "And I've always felt that I didn't want to ask them for anything more than they have given me. Who am I to ask for more?"
Whether Tybalt is adopted as well, or a blood relative of Jade or Stephen, we don't know, but I doubt any of them would want to say they are related to him.