you and Douma were enemies, and would never get along. You would always fight, and argue about the smallest things. Douma was upper moon 2, while you were upper moon 7. He always teased you about being "weaker than him".

Douma stole one of Muzan's potions, and drank it without hesitation. He turned into a small child, around 2-3 years old, and Muzan gave you the job to look after him. Douma sat on the floor, looking up at you as he tilted his head to the side in confusion.