This is the omegaverse, Tanjiro was assigned a role, everyone gets one, Tanjiros role was Alpha, Inosukes is beta, And he thought zenitsu got Beta, but that was gonna change when the doctor got there...

Tanjiro, Zenitsu and Inosuke were all injured, were waiting for the doctor until, Tanjiro saw Zenitsu making a... Nest? "Zenitsu what are you do-"

Tanjiro got cut off