Sera is a villainess from Ys VI: The Ark of Napishtim.
She is a faerie created by Ernst from gold emelas. Along with Jue and Xisa, she is sent to the Canaan islands to break the seal upon the Ark of Napishtim. She first appears on the center of the Ruins of Amnesia, where she uses one of the mirror fragments to summon a robotic monster to fight Adol, running away after Adol defeats it.
The 3 fairies break the seal upon the Ark, after which they accompany Ernst, helping him when Adol confronts him inside the Ark. After Ernst is defeated, he tells the fairies to leave the island along with his brother Geis and accompany him as his final wish.
Ys Origin and Ancient Ys Vanished