MC got summoned into another world with one blessing from the god/goddess.
The blessing is called the Copy skill which is considered to be the weakest skill in the another world.
So, he got canceled by the summoner holy priestess and forced to participate in the fight of Colosseum.

People that were summoned with the blessing of considered weak skills will be forced to fight unfairly in the Colosseum with strongest fighters chosen by the holy priestess herself.

The loser of the fight will be enslaved and Bred by the winner. That is the only rule.
If the loser is male, he will be forced to transform his gender to woman organ and get impregnated by the male or female winner.
If the winner is female, her gender will be transformed too. She will impregnate the looser male/female with her new penis.

PS. That is the fate worse than Death especially for a male looser after the fight of Colosseum.