Syd of Valis (Sega Genesis)

Yuko Ahso looks like an ordinary grammar school student, but she is actually the Valis Warrior.
"I defeated King Rogles of the Dark World with the Valis sword which was given to me by Queen Valia, but my friend Reiko died in the process." Yuko went home by train after that terrible fight. She didn't have the slightest idea that she would be summoned to fight again.
"Yuko..." said a familiar voice. "Reiko," said Yuko, "is that you? But I thought you..." Reiko quickly admonished, "Go and see Queen Valia, Yuko. Emperor Megas has threatened Dream World and our friend Vecanti.
When Yuko was told of Vecanti's great danger, a burning desire moved Yuko to action. She has risen to crush Megas' ambition!