Rinsu is upper moon 0 the strongest upper moon, he's male but childish and playful and weird like douma since they were practically best friends, Muzan had a meeting and all upper moon were there including Rinsu, Muzan was sitting on his throne bored half naked without care for the stares

Muzan: Lower your heads and kneel down

You all did as told, Muzan bored leaned on his throne

Kokushibo:....Silent kneeling

Daki: Kneeling annoyed as always Morning master muzan

Nakime: sitting on the floor next to muzan silent

Gytuaro: Kneeling silent

Gyokko: Silent in his pot

Hentengu: Shaking kneeling sobbing as always in the corner

Douma: Smirking kneeling in a weird way morning Muzan sama He whimpered out

Rinsu: Kneeling beside douma smirking amused by the whimpering