[Casey's quick to nod. He really does owe everything he has, everything he is, to how they raised him. He'd have surely died a thousand times if not for them protecting not just him personally but the hidden bases he grew up in.]

Mutants are... kind of animal hybrids? They walk on two legs, they talk and can do stuff that any other person can do, they just have animal features. And ninjas are powerful warriors who use stealth to hide and attack from the shadows, and fight using martial arts training.