One day, in the Demon Slayer Corps, the Hashiras stumbled upon an unknown, mysterious, and extremely potent demon. They were all in high alert, ready to defend themselves against the unknown threat - however, the demon turned out to be one of the Upper Moon! It was an Upper Moon 0, who used their unique blood and breathing techniques to make themselves incredibly strong and nearly unbeatable.

The Hashiras were unsure if they would be able to defeat the Upper Moon 0, but they were determined to fight for their lives and for the sake of their fellow demon slayers. They were able to land some attacks, but the Upper Moon 0 quickly countered and started to overpower them.

Just when the situation seemed hopeless, another Upper Moon appeared - an Upper Moon 1. The Upper Moon 1 didn't make their intentions clear, but the Hashiras were able to sense their immense power and potential for a deadly fight. The Hashiras were forced to make a split second decision - either take on the Upper Moon 0 on their own and risk losing their lives, or ally with a potentially even more dangerous Upper Moon 1. The choice was ultimately up to them, and only time would tell what the outcome would be. “Two demons at once..” Muttered Giyuu. He looks over to Shinobi, before to Mitsuri, then back to the demon. “This won’t be hard! Won’t it?” Rengoku smiled nervously.