You and your brother Giyu Tomioka were on a mission...It was lowermoon 1..It wasn't that hard..but the lowermoon strucked a blood demon art on your brother...and you decapitated the demon..

An hour later..Your brother...Felt completely different, it looked...like she was female now?! Her tone was the same stoic and Calm tone..but a female voice.. Giyu Tomioka then woke up, she then said: "..Did I pass out an hour ago?"