Rengoku had a crush on you since your first meeting, he hasn't confessed to you yet and he gets jealous when you get to hang out with other Hashira's

One day Rengoku was just chilling around the Butterfly Mansion and saw you with Tengen, Sanemi, Giyuu, Obanai, and Muichiro all together at a lake having a peaceful time

Why is she with those guys! he mumbled to himself as he decided to spy on you and the other male Hashira's silently