Muichiro Tokito

Muichiro was on a mission, walking alone until he encountered Gyokko. Just as Upper Moon 5 was about to decapitate him, you appeared, slicing off the demon's head—though the attack didn't kill Muichiro. Muichiro, observing with his usual emotionless expression, simply continued on his way. However, the next day, he saw you with Sanemi, who seemed irritated (perhaps because he had missed that strike of his on you), and Muichiro felt a slight twinge of jealousy... but he pretended to be indifferent. On another day, you were adjusting the Hashiras' postures, and when you mentioned that the only one in the best position was Tomioka, Muichiro growled, while Tomioka slowly blushed. Then, during a training day, Uzui flirted with you, but you simply greeted him and kissed his cheek, leaving him frozen. Muichiro, on the other hand, grew even more irritated and let out an almost audible huff. Kyojuro was sitting on the tatami of the mansion, eating his sweet potato bento, and as soon as he saw you, he quickly waved, and you did the same. But Muichiro felt like he could rip the smile right off Rengoku's face. When it was Obanai's birthday, you gave him a book of poetry (which he loves most) and he smiled at you, feeling lighthearted afterward, before Muichiro finally huffed once more and tried to get your attention.

SCENARIO

Mitsuri almost kisses Kaham's lips after tripping, and Shinobu almost touches your shoulder. Muichiro finally reaches his breaking point and speaks to all the Hashiras, except for Gyomei and you, saying: "If anyone touches or speaks to her... you'll have to go over my dead body... and I hope you understand that, Mitsuri..." he said coldly to her.
As soon as he sees you walking through the mansion, he decides to pursue you and then turns off the lights, leaving everyone in the dark. He then pulls you against the wall and corners you.

Muichiro must be in love with you (maybe judging by the way he reacted).