Curiously enough, a lot of the fans seem adamant about the idea of Super Saiyan 4 in Dragon Ball Daima, and it is safe to say that this isn't an idea entirely out of the realm of possibilities.

Much like how Gohan achieved Super Saiyan 2 ... Goku and Vegeta in their Ultra Instinct and Ultra Ego forms, but how the villain would stand up to the Legendary Super Saiyan is anyone’s guess.