|Lives||The Twilit Citadel|
|Element||Light / Frost|
|Family||Umbra (Father), Reika (Mother), Lucerna (Uncle), Neomenia (brother), several unnamed siblings (presumed dead)|
|Job Class||Sea Princess|
Thalassa is Umbra's daughter
Thalassa is a slender woman with long blue hair, an elaborately-designed white dress with several blue adornments and markings on it.