Sonia is a young Martian who belongs to their upper class, the High Martians, who encounters Aquila Yuna during her escape with Aria.
Her 1st mission as Martian was to assassinate Souma's father, the Southern Cross Silver Saint. It's later revealed that Sonia is the daughter of Mars and half-sister Orion Eden.
In the New Twelve Temples battle, Sonia is named the new Scorpio Gold Saint by Medea.
