No.9567081 ViewReplyOriginalReport
back then when Kaguya was exiled on Earth, Eirin alien-abducted a girl from Earth, brainwash her, mutate her with extremely watered down Hourai Elixir, and name her "Sakuya". (from Kaguya's real name, Konohana Sakuyahime). heck, the last kanji for their name is the same.

Eirin made this Sakuya her personal attendant. she use Sakuya to fulfill her (mostly carnal) desire for Kaguya. this Sakuya has been brainwashed to be a perfect maid, and see whatever life-threatening abuse from Eirin as love. after all she didn't die, for she's Hourai-infused.

when Eirin was sent as part of lunar emissary to retrieve Kaguya, she made Sakuya kill everyone. then she killed Sakuya, arrow piercing her heart.

"you've been such a good dog. i myself dont want to stain my hands with their filty blood, knowing such sin will haunt me for the eternity i'll spend with Kaguya."