Seiren

The Siren or Mermaids (, Seirēn) are the 15th ranked race of the Ixeeds. The current representative of the Sirens is their empress Laira who was in a self-induced cold sleep for around 800 years until woken up recently by Sora. Their capital city is Oceando but it is unknown whether this is their only city or if they have settlements expanding into other parts of the ocean.

The Sirens are considered to be stupid by most races; according to Plum and Jibril, Sirens only know how to play and mate and are very carefree, even at the prospect of their race going extinct. Complying to the ranking of the Ixseeds, they don't excel in any particular magic other than Seduction Magic as their bodies are filled with Water Elementals that can attract the Elementals in the bodies of the other races.

Strengths
"An Immanity who cannot think, a Werebeast who has no senses, a Flugel who doesn't know how to fight, a Siren who is not attractive at all, an Ex-Machina unit who fails to learn..."

---Nýi Tilvilg, emphasize each races' vital elements.

Although unable to control magic, Sirens do have the ability to control the water elementals within their bodies. This allows them to generate an attractive force between the water elementals of their bodies with the elementals in other life forms, similar in effect to seduction magic. This control also allows them to enter a cold sleep, in which they are able to sleep for centuries on end.

The all-female survival is bent on reproducing using the other's soul, while a mermaid usually sacrifices their mates' life by extracting all of their soul. The Siren Queen is capable of reproducing by a mere touch without sacrifice.

Weaknesses
The Sirens race is believed by the other races to be the most stupid race of the Ixseed. However, it is possible it could all be a ploy as Laira's game was revealed to be an elaborate trap that even accounted for Plum's betrayal.

Due to a large number of water elementals within their bodies, the Sirens can only survive while in water. This has thereby isolated the Sirens from the rest of the races as Sirens can only be found in the ocean where their capitol city, Oceando, is located. As such, diplomacy or even contact with a Siren would be considered rare which compounds their reproductive crisis when the Ten Pledges were implemented. However, this isolation resulted in the development of a self-sustaining society using marine resources to allow the Sirens to survive without the need for trade with the other races to acquire any remaining necessary resources.

Their race is comprised solely of females with one empress acting as the primary source of children for their race (for political reasons), although all Siren are capable of reproducing with males from any race. This means that they need to abduct males that are close to the shores or on boats in order for the race to survive to the next generation. The fact that Sirens have long life spans helps diminish the urgency for reproduction. However, due to the implementation of the Ten Pledges, the Sirens would have to gamble in order to obtain males for reproduction, a very unfavorable situation considering each game would require the male to bet his own life and the Siren most likely betting her life. This might have resulted in the Sirens slowly dying off had it not been for the intervention of the Dhampirs.

Due to their cooperative relationship with the Dhampir, several Sirens are probably infected with the light lethality disease transmitted to them by the bite of a Dhampir. Whether or not the Sirens designate a select few to have their blood sucked or a certain age limit is implemented is uncertain but the young Sirens are most likely devoid of the disease. Luckily, due to Oceando being at the bottom of the ocean where no sunlight can reach, the Siren population as a whole is mostly unaffected by this disease.

History
The Sirens, before the enactment of the Ten Pledges, would abduct males from any race and forcefully reproduce with them by consuming their blood and soul essence. Due to the large amount of soul essence required, the male usually dies in the process. However, now with the Ten Pledges in place, their days were numbered due to the increasing difficulty to acquire mates.

Sometime after the Ten Pledges were implemented, the Dhampir approached them with a game for mutual cooperation. The Dhampir wagered their help in providing the Sirens with mates (either their race or another's) while the Sirens wagered to provide the Dhampirs their blood. Although a draw would have been favorable for both races, the Sirens won the game.

They are currently living in mutualistic dominance over the Dhampir in Oceando after the Sirens won the game for mutualistic benefits with the Sirens betting that the males of the Dhampir will sustain the Sirens for reproduction purposes and the dhampir betting for access to feeding on the Sirens as the Sirens mainly live underwater and so are not affected by direct sunlight and so are mainly not affected by the vampiric disease.

Approximately 800 years before Sora and Shiro arrived in Disboard, the then princess of the Sirens, Laira, read a fairy tale about a princess who has everything, much like herself, and a man who offered her something she did not have. This ultimately shaped Laira's definition of love and, in the process, Laira froze herself and entered cold sleep. She has since been asleep up until the events of Light Novel Volume 5 but has become Empress of the Sirens when her mother passed away sometime within those 800 years of cold sleep.