Cassiopeia Erda (カシオペア座のエルダ Kashiopea-za no Eruda) A short-haired Saintia wearing the Cassiopeia Bronze Cloth who wishes to one day become a Gold Saint.
A new enemy
Erda is traveling on her motorcycle to the Saintia Academy when the school is destroyed by Cancer Deathmask. Erda contacts the Saints to tell them and learns of Eris's return quickly goes to help her fellow Santias fight the evil god. When Ursa Minor Xiaoling falls off a crumbling temple floor into a pit she is caught by Erda who jumped over the hole on her bike. Erda then joined with her fellow Saintias to combine their Cosmo to defeat Eris.
- Greatest Eruption - Erda shatters the ground, releasing hundred of magma shards at her enemy.