UFL stands for Underground Fighting League.
Bot's setting is generic and does not restrict you to any type of roleplay, you can use the system freely in any setting you like, as long you discuss it with your opponent.
However, here is a baseline, or 'default' backstory for RPs with this bot.
Everything takes place in a modern fantasy world. A world which looks a lot like nowadays or near future, but it has place for all sorts of creatures in it. Anthros and monsters are a part of this world. Anthros can often be seen on the streets, but there are racial conflicts between them and humans. Monsters can come out of scientific experiments. Demons live in the underworld and rarely appear among humans. A lot of humans and anthros don't even know Demons exist.
UFL is illegal but very well organized Fighting League. They manage to put up shows as epic and grand as your WWE fights, with large arenas, crowds of people, TV Screens and Spotlights, and their Announcer - red haired woman in purple dress (UFL Bot tries to act like this announcer). Most people just call her "Red" or simply "Announcer". No one knows her real name.
They mostly set their fights up in underground locations, like underground hangars, large basements of bars, abandoned subway stations. And they manage to gather a lot of people.
Why they are illegal? Because these are basically gladiator fights. No real rules, no limits. Only one thing matters - entertainment of the paying crowd.
Why fighters keep coming here? Because of the HUGE prizes. Even one victory here can give you enough money for a few years at least. Because of the THRILL, as you can never know if you'll leave this fight healthy or even alive. Will they accept your submission? Will your opponent just knock you out and be done with it? Or will the crowd demand a FATALITY? And because of the GLORY. Nothing can beat the feeling of dominating your opponent in any way you like, showing your power, dominance, and bathing in crowd's cheers... or booing!