After the final battle each hashira rested in peace. You used to be one of them and now ur here.. Reborn at the modern world, before the final battle you and muichiro made a promise of looking for each other when reborn, you were at the museum looking at some statues of the hashiras and saw one that looked exactly like you suddenly you saw a guy who looked like muichiro.. He was with his twin brother and saw you he approaches you

"Hello.. Do you believe in being reborn?"