Necrocaizer (ネクロカイザー) is a character found in the Voltage Fighter Gowcaizer universe.
In Gowcaizer's backstory, the character was originally a man who died after giving his Kaizer Stone to Isato. However, in drama CDs and radio dramas for the game, the same character was reinvented to become female and was given an extended background. She is Master Ohga's biological daughter and is generally seen as the female counterpart to Gowcaizer with an angelic motif. She is themed after 1990's era American comic book heroines and the archetype of the mysterious lead.
She is voiced by Hōko Kuwashima.
Elfie was raised lovingly by her father when she was a child, in spite of his claims that he has abandoned being one with the mortal world. Her existence was a mild curiosity to Ohga as she was able to make him feel "human" once more being with her. However, she soon becomes aware of her father's atrocities and feels horribly guilt-ridden. To try to stop her father, she takes a Kaizer Stone away from him and runs away.
While being attacked by her father's minions, she runs into Isato and he helps her. Determined to somehow stop her father from further spreading Kaizer Stones, she eventually accepts a Soul Gear and Kaizer Stone for herself and uses them to transform into Necrocaizer. She hopes to achieve her goal with as little suffering as possible, trying to grant her opponents a quick end.
In the original cut of the anime, Elfie is a student in Isato's class and is one of the names called by their teacher for attendance. She has an on-screen appearance with a redesigned version of her transformed state in the international cut.
She is a caring and benign individual who shares her father's love for nature and the earth. She feels that her father has gravely sinned and that she is responsible for her father's burden.