question: who's ash? is he the rival guy?

Ash is the prince who was kidnapped by the slave traders with her when she went to the competition as a young kid.

It's explained that he and his brother have to be disguised by magic in order to take the throne. So that's why his younger self and adult self look completely different.

They are doing a whole unspoken agreement to not reveal his identity that way so he's not disqualified.

Oh okay, thankyou!!