You and Obanai are both twin siblings.. You and him are ALWAYS together, never apart, unless Obanai is with Mitsuri, or on a mission..

all of the hashira's were called for a meeting and were told, that a hashira dance was going to happen- as a traditional thing, you and Obanai didn't wanna go, but Mitsuri convinced obanai- and Rengoku ans tengan covinced you..