Viral 1-on-1 butt-motion controlled fighting game Ketsu Battler has come really far since its December 2024 release on the Nintendo Switch. Though the basic premise of putting a Joy Con in your pants to control fighters with swords in their butts may sound like a one-off gag, the title has since been recognized for its competitive depth and even included in GBVS Cygames Cup 2026 and EVO Japan 2026 side-tournaments.
Most prominently, Ketsu Battler held an official collaboration with Granblue Fantasy Versus: Rising in January 2026, with Beelzebub and Narmaya joining the roster as guest fighters. Talking to Famitsu ahead of Ketsu Battler’s major Ver 2.0 update, the game’s developer TomozoP (affiliated with KAYAC) talked about how this collaboration came about in the first place.
According to the developer, the offer came “completely out of nowhere,” and he basically considers it a miracle. Tetsuya Fukuhara, the creative director of the Granblue Fantasy IP, approached his team specifically saying he wanted Versus Rising’s Beelzebub and Narmaya to appear in Ketsu Battler. “At first, I figured it was a joke,” TomozoP says, “but as discussions progressed, it became clear they were serious about it. That’s when it hit me, ‘Oh wait, they weren’t kidding’ (laughs).”
When he asked Fukuhara what had led to all of this, he found out it was connected to voice actor Hiroki Yasumoto – who is known for fighting game roles like Street Fighter’s Guile and BlazBlue’s Azrael – having played Ketsu Battler during a live streaming show. The rest of the story is even more surreal: “I’d posted on X that, as a longtime BlazBlue fan, I was thrilled that Yasumoto had played our game. Then Toshimichi Mori, who was the producer of BlazBlue at the time, quote-retweeted my post. That was how Mori first learned about Ketsu Battler. He then invited Fukuhara to play it together… which, apparently, is how Fukuhara ended up discovering Ketsu Battler.”
While TomozoP was of course overjoyed by the collaboration itself, he was mostly taken aback by the string of coincidences that lined up to make it happen. “Those kinds of character reveals and surprise announcements are something I think every game developer dreams of doing at least once. I never imagined that Ketsu Battler would ever get a moment like that.”
It’s worth noting that Ketsu Battler originated from a browser-based mini game TomozoP created for a one-week game jam. He later submitted the project to a contest held by CoroCoro Comic and won, gaining support to publish a full-blown console game from the company. With this origin story in mind, Ketsu Battler’s rise to popularity among Japanese fighting game veterans is even more inspiring.
Ketsu Battler is available for the Nintendo Switch and Switch 2.
