Looking for a manga

So I think it's shounen ai or not but there's this really pretty boy who likes to make peculiar umbrellas then there's this other male that always takes care of him, btw the pretty boy doesn't wear his underwear and the other male always asks him to wear them . The pretty boy turns out to be a skilled idk killer but he's very good with his knives , the setting is in ancient japan i think . That's all I remember I'm so sorry , please help me find it (づ￣ ³￣)づ thank you very much !!!