If you're talking about that dude at the start, pretty sure he was just a stalker who couldn't take "no" for an answer
He's talking about "the price of a champion" (p.8) and says the girl "asked for help from various men" (same panel), so I guess she wanted to pay for his help with her body, which isn't enough according to him.
As to why they still banged, it's relatively useless to know, it just leads the reader to think she also banged other guys for help, but she didn't get what she wanted and still payed the price each time.
That seems very silly and unnatural to me, but that's how the story is written and I can't change that.
"It's the law of the strongest." (page two): I guess it means she can't do anything about it if he wants to have a good fuck, she can't even get payback by legal or illegal means
So what, the law says it's fine to get r*ped on the streets and for everyone to see? Even if not rape, I guess people would mind their own business if the guy is strong. And the girl has to accept she's being taken and can't do anything about it too!
That's such an idiotic and infuriating setting.
So she reached out to him, he's no stalker imo. And refusal is clearly not an option in this story, if you're on the weaker side.
However, women are usually weak in a historical swordsman settings, so you'll get free violence + erotica reading this. Just because the ennemies are supposed to be mean and the environment is supposed to be hard on people.
I think we got the point already just from seeing the two dudes killing each other, so yeah but no, this story won't be going to my reading list.