The Sirens' Empress and full representative, she has been hibernating for eight hundred years while proposing a game: she would give everything she possessed (including her Race Piece) to the one man who manage to wake her up.
The thing is, she would only wake up if she manages to fall in love, creating a very complex and difficult "Real Life Romance Game".
She is a member of the Council of Eighteen Wings, as well as custodian of the National Library of Elchea, won from Stephanie's grandfather five years prior to Sora and Shiro's arrival.
After the siblings defeat her in shiritori (in which she bet The fourteenth-ranking Exceed, the Warbeasts, distinguishable by their ears, claws and tail, are one of two races without magic ability (the other being Imanity), which is more than made up for with heightened senses and telepathy.
The tenth-ranking Exceed, the Ex-Machinae are an ancient race of Mechanical Lifeforms that were created by a long-forgotten Old Deus.
Their race form communities by linking individuals into a Hive Mind, allowing them to quickly learn and adapt.
With Tet banning violence upon ascent to godhood following the deaths of the rest of his kin — including their creator, Artosh — they have since taken to collecting books across Disboard, storing them in their capital, the floating city of Avantheim .
Like the Elves, Flügels are collectively ruled by the Council of Eighteen Wings.
With Sora and Shiro's ascent to King/Queen of Elchea, they begin a campaign of reclaiming lost lands, while Stephanie handles bureaucratic affairs.
In truth, Plum is the very last male Dhampir, forced to go around in drag to avoid an unwanted (and potentially fatal) encounter with the Sirens.
The fifteenth-ranking Exceed (thus sandwiched between Warbeasts and Imanity), the Sirens are an all-female race of aquatic creatures, living in Oceando, the great sea between Andalucia (home continent of Elchea) and the Eastern Federation's home islands.
Unfortunately, due to the low survival rate of males mating with Sirens, the Dhampires (and Sirens) were nearly driven to extinction, its male population reduced to a single preteen who is now forced to dress up as a girl.
A female Dhampir who requests for Sora and Shiro's help in dealing with both Dhampires and Sirens.