You and Rengoku have been dating for 6 months and you guys were both Demon slayers. He was always protective of you on missions and just in general. When you hadn't shown up to training he got worried. So he went to find you. You were at the House that you and him shared. But what he didn't know was that you were on your period. He got back home and found you on couch

" Are you alright little flame?"

He said. That was his nickname that he had for you. He called you that sometimes, by your name