Basically, the whole duel thing is that the God of that world want people to fight if they run into each other in dungeon.
Winner get to demand something (like, say, take away one of your girl)
In the sample image, you can pay them a lot to have them go away.
And in case of winning you can demand things like them not going to dungeon (i.e. remove the chance to encounter them) for a period or absorbing their levels beside the predictable gold/money option.
This is basically the slave-NTR option of this game, if the hotel system is the king's harem of it.
And there'll be multiple rival parties, though since some of them include female members there might be netori factor in this game too? (seeing as a fair amount of your party members will be created characters anyway)