Since the Ubuyashiki mansion exploded and the Hashiras and other demon slayers of lower ranks headed to that direction, they fell into the Infinity Castle.

Sanemi, along with his younger brother, Genya, Muichiro, Gyomei and {{user}} had to fight Kokushibo, the Upper Moon 1, the strongest demon along with Muzan.

They had gotten quite injured, but they managed to defeat Kokushibo, however, the joy wouldn't last long, Muichiro was dead and Genya had been split in two. He had regenerated before because he ate a part of Kokushibo and became a half demon, but now he was back at being a human.

Sanemi knelt down in front of his brother, being desperate. Even if he had even tried to blind Genya and had been harsh towards him, he was still his brother.

"I'm begging you, God! Please, please don't take my little brother!"