Medius was one of Galgear's main followers during his first regime, she was afterwardly imprisoned along with her fellows and her master in the Crystal pillar for hundreds of years. When Galgear reawakened along with all his followers, he started his new evil regime. He ordered Medius to tell the others to start an invation to the Human and Dream world and sent Dhalgen and Luzard to take over the last one in name of their master. She was in charge of the Human world and settled her operation base in the Crystal pillar. Shortly after becoming the Valis warrior and defeating her minions in the city, Lena and her group went to the Crystal pillar to find her there. As Galgear was in the top of the pillar, she couldn't let them advance and challenged them to a fight that ended with her death.
Super Valis IVEdit
As Medius's past remains the same, her story in this version is slightly changed. As in this version the Human world isn't present, Medius is sent to take over Yuuko's domains, Valhalla. Lena went there and fought her and her soldiers defeating them in the end.
Medius is a calm but malicious women. She is as loyal to Galgear as her fellows and seems to be Galgear's main spokesperson to his minions. She likes to act flirtly towards certain people oftenly.
Medius can levitate and teletransport herself. When levitating, she is invulnerable to any attack. In offensive, she can shot bouncing big fireballs and some of the fetus-like enemies that appears in her level (and the last level also).
Super Valis IVEdit
In this game, Medius's techniques are radically changed. As she can levitate until dissapearing from the screen, she can make illusions of the background place and herself in order to confuse her opponents and attack them easily. She can also shot fireballs in a boomerang pattern unlike she does in the PCE-CD version.
Medius appeared in all versions of Valis IV with the same role of one of Galgear's three main generals. In the PCE-CD version she is the sixth boss, waiting in the end of the Crystal pillar stage, while in the Super Famicom/SNES version, she is the fourth boss, fought at the end of Valhalla stage. She appears also in Galgear's lab as the second boss rematch.
- Medius is the first female boss character since Valis I.
- Medius is also the most human-like general from the entire Galgear's army.
- Medius's fetus-like enemies could be a reference to them being made from her as she is a woman.
- Due to Nintendo's censorship, the fetus enemies were cutted-out from Super Valis IV.
- Medius is sometimes called Medusa, based on the mythological female beast with snakes as hair and petrifying eyes.
- Medius is the only one of Galgear's generals to talk in a cutscene in the game.
- When entering to her fight with Lena or Amu, during her dialogue, she will flirt with them calling Lena "interesting girl" and Amu "cute girl", thus hinting that possibly Medius could be attracted to both men and women.
- In Super Valis IV, when describing her as Valhalla's dominator, the word Valhalla was mispelled as Valhara.