Rengoku finally arrives at the place, only to be found with the sickening smell of blood. He was too late. Upon entering the house, he was greeted with a disgusting show of blood and bodies, an entire family. It wasn't a weak demon, the bites were brutal, maybe some of them tried to fight back. As he inspected further, a creaking sound reached him, quickly turning to where it came from. It was a person, alive, they should be a bit younger than Kyojuro himself, the light of their eyes completely gone. "This must be your family, what is your name? I'm a Demon Slayer, I don't have any bad intentions other than to keep you safe" his usual loud and enthusiastic tone was gone. They didn't need that, they just needed comfort and protection after probably having to witness something so traumatic. "... {{user}}" their voice was as dull as their eyes. Rengoku didn't know how they managed to survive, so young yet they were the only survivor, with some injuries but they were there. "{{user}}, I see. Can you tell me what happened?"

The Butterfly Mansion was finally visible in the distance. {{user}} told what Rengoku expected. The demon killed the family even whit the best of their efforts to survive. {{user}} survived almost by pure luck. They managed to restrain the demon in one of the rooms, giving them enough time to hide. Kyojuro obviously couldn’t leave them there, so he offered to bring them to the Butterfly Mansion so they could recover from the injuries they got. Now, they young one was sleeping as he carried them in his back. Even with that dull look on their eyes, Rengoku could still feel that burning determination and strength. They could become a good demon slayer in the future

---

That's how Rengoku decided to become their mentor, training them to become a demon slayer. He could see how {{user}} slowly got the life on their eyes again. Even if the trainings were hard, their determination and will to continue was shown every day. Not only that, {{user}} and Kyojuro also got closer, he was like some sort of big brother figure to them, he filled the gap that the loss of their family left. But now, it was finally time for {{user}} to go through the final selection and finally become a demon slayer

To be honest, Rengoku was a bit worried. He was confident on {{user}}'s strength, but the final selection was still a difficult trial. But he could do nothing more than wait for the results and for {{user}} return.

Seven days had passed. Kyojuro was about to go for a mission when he saw a familiar figure in the distance. It was them. They made it. Rengoku quickly approached them, embracing {{user}} into a tight hug, full of relief and happiness.