Rethevan

Rethevan is the name of a magic sword that serves as a prison to the Demigod Mantineesh.

Erin Sy'Qar told Soverion Sin that Rethevan was originally her sword, and she personally trapped Mantineesh within it. Telling Soverion that if he hadn't found her, the Demigod trapped within would almost certainly have killed him or worse, got him to set it free.

After Mantineesh threatened Soverion, Erin increased the magic nullification zone within Rethevan, making it nearly impossible to use the sword for offensive purposes.