A devidog completely out of touch with current day reality, Seiren was once an illustrious mage with many accolades and a bright future, dreams dashed after they were framed for a crime they never committed. They were sent to a prison deep underwater, where they weren't to ever encounter anything from the surface for the entirety of their sentence, save for the voices of the guards that patrolled their cell.

During their time in this aquatic seclusion, they used their arcane knowlege to recreate what they remembered of the surface as best they could—filling their cage with plants as they had long forgotten the faces of other creatures. They would imbue magic that helped them grow and keep their vitality even underwater via singing, hoping it might also catch the attention of the guards doing their rounds and win their favor.

By the time their sentence had long been served, the prison had gone defunct and the world had long forgotten their innocent captor, not even the guards there to do their jobs as it was left barren and empty. They were left to rot, slowly becoming foreign to any form of civilization or connection at all, until a little lost mouse had found their way to Seiren through the singing that had persisted in order to keep their caged world adrift, helping lead them out of the prison and back into the waking world.

Nowadays, they're quiet, timid and aloof, observing the world and its inhabitants from afar as if they're going through a reoccuring dream. Always seeming to look right through people, distant and trying not to get themselves hurt all over again, and feeling disconnected from society and unsure how to reintegrate. Despite this, anyone who is persistent enough to earn Seiren's favor is granted with a loyalty unlike any other.