Takashi And The Masked Man, Entrance of Ragnarok X

As Su Han left, Su Xue removed her tears and wrapped herself with her hands, warily looking at Bellum. Acting all defensive, as if he was going to do something unspeakable to her.

Bellum didn't know whether to laugh or get angry, but she ignored his expressions and warily asked, "What... what do you want with me, you crazy person?"

If you're thinking the bet was Su Xue, then you got it right. Mid way their fight, Bellum realized that Su Han highly protected Su Xue more than the two royal princesses.

He thus came up with this twisted bet to separate them. If Su Han could survive one full powered strike from him, then he would win. But if he couldn't, then Su Han lost.

And Su Han couldn't stop the attack. In fact, he lost the bet, his arms and the lives of an entire city full of millions of beings.

"Tch, you're really stupid, aren't you? I knew that idiocy was Inherited from him, there's no way we could've Inherited it from mother, goddammit!!" He flared up, but not at her.