Deku is the next Avatar confirmed.

Deku: I can win!! I feel great!! I can do this!!! AHHHH-
Super Funky: Uhhh, what are you doing?
Deku:…Nothing.
Super Funky: Really? Because it looked like you were chanting to yourself.
Deku: Are you in my head?
Super Funky: Yup. Don't worry. Supposedly, I should fade into your subconscious…sooner or later.
Deku: Okay, so, what now?
Super Funky: By my estimate, these new quirks should give you just enough power to capture the bastard that shit-talked your friend.
Deku: And?
Super Funky: Let me put this in a way you'll understand. You can win!! You feel great!! You can do this!!!
Deku: OH HAH HAH!!