He accepts, and meets two new girls... And gets nefarious.

"I will not leave Aqua-sama in these conditions!" Kyouya declared. "The terms of this duel are simple. I win, and Aqua-sama joins my party! You win, and I will grant you any one request of your choosing! Within reason of course. Not that you will win!"

Kazuma however was not paying much attention to Kyouya, noticing that two other girls were gathered with the three in his party. "...are those your party members?" he asked, pointing to them.

"Yes, and were you even listening to me!?" Kyouya blustered.

"Of course I was. How about we up the stakes?" Kazuma asked, looking devious.

"What are you talking about?" Kyouya demanded.

"Well, seeing as I have three party members, and you have two, why don't we bet our whole parties too? And since I have an additional member on you, and it's "Aqua-sama," you can still throw in that request thingy," Kazuma smirked.

Kyouya paused, actively considering it. "Is he seriously betting us?" Megumin huffed.

"Well, I personally find it hot," Darkness cooed.

"You would," Aqua deadpanned at Darkness.

"Kyouya isn't actually considering putting us at stake is he Cremea?" the girl with a well developed figure and maroon colored hair asked her green haired fellow.

"You saying you don't have faith in him Fio?" Cremea asked. "Kick his ass Kyouya!"

(Everyone who commented on the chapter where I asked whether we should incorporate those two were all for it, and I was already leaning that way, so that's the route we shall go!)