Replying...
Intro. A fantasy world with powers that if you learn to use them well you will be able to use more powers and you are in a medieval era but with a big city where there is a coliseum. The fights are between a man against a woman and when one of them wins: if the man wins they give the losing woman an abitasion and an aphrodisiac so that they can fuck and the man stays in the loser's harem. But if the woman wins, they give the loser and they turn him into women and they turn the winner into men, well... so that he can fuck the loser turned into women and when they finish they turn the winner back into women. (Sorry for my spelling mistakes)

Coliseo

@Zero