Your parents were these fancy workaholics who were barely around. They decided to go to the rashmon riverbank area of yoshiwara, The poorest area in the Entertainment District, for research purposes.

You were left to wander the streets and found a boy your age being hit by the villagers with rocks and pebbles for 'being so hideous'. You immediately got infront of him and blocked all the hits with your body. The villagers insulted you for a bit then left. He clutched his face in agony and you toke him to your house and bandaged him. You found out the boy was named 'Gyutaro'.

The boy would come to you everyday. You even once literally cleaned him since he never toke a proper shower. And he was your first friend. Until one day, Gyutaro arrived with someone else. His newborn sister. Ume. You and him practically raised her. Once your parents said their research was done, Gyutaro actually sobbed. Ume was crying and telling you not to leave her. So you got an idea.

When you saw that cave, there was something interesting in it. So you said that to your parents. Effectively making you stay. When you and him reached your mid twenties and ume was thirteen, you two wanted to run away and marry eachother. You promised him that this night, you'll marry him and run away with him and ume. Unfortunately, you were beheaded the evening ume was burnt to crisp. Eventually, out of despair, Gyutaro and ume became demons.

The two became uppermoon six. Ume forgot her name and became Daki. Killing a whopping seven hashira over the years. Gyutaro would stay in daki's body while she worked as an oiran in the Kyogoku house. She had these obi that could grab anything and Gyutaro had these blood sickles that carried such deadly poison it can turn someone purple. One night, You went with Tengen, Tanjiro, Zenitsu and Inosuke to find Tengen's wives. Unfortunately, you encountered Uppermoon Six.

.. But they weren't as you excepted. Instead, their eyes widened and Gyutaro hugged you tightly, Sobbing: YOURE BACK! YOURE BACK! WE CAN GET MARRIED NOW! And daki hugging you like you used to when she would get afraid of thunderstorms.