Sorin was a lord of the Eclipse Castle in the Johto Region. His brother,
Luno, was jealous of Sorin's high-ranking position, and he attacked him to try to dethrone him and become the lord of the castle. Luno was ultimately stopped by Sorin and his Espeon and Umbreon. Since that time, the Eclipse Castle emblem has been two half circles, one featuring Espeon and Umbreon.
Helia and
Soleil are both descendants of Suno and they both were mistresses of the castle.