Ла Андромеда Прометіум II

Ironically, she puts her daughters, Maetel and Emeraldas in a difficult position similar to how her mother, Millennial Queen from the Queen Millennia series (Mother of Yayoi, and Selen) did to her and Selen, where they must fight for their own beliefs and stop the Queen. Initially however, when Promethium had a human body, she was a motherly queen who loved her daughters, Maetel and Emeraldas. But as she desired for eternal life, without having to suffer from illness, aging, and starvation, she allowed herself to be converted into a cyborg, as shown in Maetel Legend. Soon after, she realizes that she is losing her human qualities, most importantly the quality of love.

As a result, she regrets having a mechanical body despite its advantages. When she realizes that her mind is finally out of control, she asks Maetel to kill her as shown in Space Symphony Maetel. Although Maetel and Emeraldas supposedly killed Promethium in Space Symphony Maetel, Promethium's evil spirit still lives.

In the Galaxy Express 999 TV series, Promethium finally gets killed by Maetel and Tetsuro, with the destruction of La Metal. [Queen Millennia Movie] Yayoi Yukino, Promethium II opposes Lalela and her plan to wipe out all mankind to gain etneral spring for La Metallians, unlike in the anime where she is pressured by her own mother, Promethium I to destroy mankind in order to keep La Metal's traditional cycle going. In the end, Promethium II dies after weakening Lalela by shooting her with a pistol. [Queen Millennia TV series] Promethium, also known as Yayoi Yukino is the princess of La Metal, and was to become the next Queen Millennia.

However, she betrays La Metal and the current Millennial Queen for the sake of the earth and a young boy named Hajime. After joining forces with her older sister Selen, she manages to save the Earth from total annihilation. It is likely that she is the same Promethium appeared in the Maetel Legend, though Queen Millennia series and Maetel's series (Maetel Legend, Space Symphony Maetel, Galaxy Express 999) could possibly irrelevant.