The Sun hashira

Dad!Yoriichi being overprotective of Tanjirou and trying to get him away from all the nine Pillars, because he knows they're in love with him.
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"Tanjirou, don't!" Kie scolds him lightly when the little one grabs a bunch of Yoriichi's hair.

"No, it's fine," Yoriichi assures her again, pulling the toddler closer. "It's alright."

Then he meets baby Nezuko, and Yoriichi decides to keep coming back to the Kamados; he wants to help them as much as he can.

It's difficult to find free time to do that considering he has a lot of responsibilities as the Sun hashira, but he makes an effort.

Time passes and the two eldest start calling him Dad Yoriichi and their father just Dad, however, the Pillar tries to correct them every single time, even though it makes him feel warm and fuzzy every single time.