Python subclass with new, init and method

I'm trying to create a subclass in a particular case and I can not attach attributes or method to it. I think the new / init usage is not clear to me but I could not find ways to do that from the internet.

Here is a minimal working toy example showing what I am trying to do.

# I have this
class Human():
    def __init__(self):
        self.introduction = "Hello I'm human"


def create_special_human():
    special_human = Human()
    do_very_complicated_stuffs(special_human)
    special_human.introduction = "Hello I'm special"
    return special_human


# I want to create this class
class SuperHero(Human):

    def __new__(self):
        special_human = create_special_human()
        return special_human

    def __init__(self):
        self.superpower = 'fly'

    def show_off(self):
        print(self.introduction)
        print(f"I can {self.superpower}")



human = Human()
special_human = create_special_human()
super_hero = SuperHero()
super_hero.show_off() # fails with error "type object 'Human' has no attribute 'show_off'"
print(super_hero.superpower) # fails with error "type object 'Human' has no attribute 'superpower'"

I want to create the subclass Superhero, and I need to initialize it with what is returned by create_special_human(), because this function is very complex in the real case. Moreover, I can not modify the Human class and create_special_human().

I am aware that the returned type is Human, which is wrong, but I don't know why that happens.