Aselia The Eternal

In Aselia the Eternal, you play as Yuuto Takamine, an orphaned high school student taking care of his younger sister Kaori. A strange event transports them into a parallel world called Phantasmagoria (make as many Spoony inspired jokes as you want, I certainly made them), a war torn world in which a race of female elementals called spirits are used as weapons in service to the human rulers of their respective kingdoms. Soon after the arrival, Kaori is taken hostage by the local king and Yuuto is forced to fight as an Etranger, the world’s term for someone from another world and trained to essentially be a supersoldier, and given a powerful sword that slowly seems to be driving him insane.