Laira Lorelei (ライラ・ローレライ, Raira Rōrerai) is the current empress of the Siren after her mother passed away. She entered into a cold sleep and has been sleeping for 800 years leading to the events of Light Novel Volume 4 of the light novel. However, after encountering Sora in Light Novel Volume 5, she has awoken from her cold sleep and has willingly joined Oceando, along with the Sirens and Dhampir, into an alliance with the Commonwealth of Elkia.
Like other Siren, she is mainly humanoid with dress-like fins on her feet and pointed ears. She has wavy blue hair and a youthful face as well as a snow-white body that is decorated with strips of gold. The lower half of her body has attractive scales on it, which reflect the light in the room.
She was bored with life and seeks 'pure love' as she was born with everything: wealth, beauty and 'love' from everyone. During her debut, she acted like a spoiled child - she does not seem to care about how long she had been sleeping (V5C4), while also deriving pleasure in rejecting people in the most brutal way when they are deeply in love with her.
Turns out, her definition of "pure love" is "unobtainable love" in which no matter how much she loves the other person, the person will not reciprocate it. As such, it was the goal of her game to find this "unobtainable love" (in which Shiro found out before Sora despite deciphering people's intentions supposedly being his strength). After Sora defeated her, she has since fallen in love with him to the point of even calling him her "Prince" or, "Emperor".
She also displayed incredibly masochistic tendencies towards Sora, always asking him to physically and verbally abuse her. She would lend out the Siren's Race Piece in exchange for Sora stepping on her.
As a Siren, she has the ability to manipulate the water spirits within her body. This enables her to attract the spirits within other living things generating something similar to "seduction magic". However, due to the abnormally large amount of water spirits contained within her, Laira's ability to attract spirits is greatly enhanced even to the point of being able to seduce Sora and Shiro's group with the exception of Sora and Shiro themselves, regardless of their gender.
Laira, like any other Siren, is also able to undergo a cold sleep in which she can sleep continuously for a thousand years or more. She does this by encasing herself in ice (it is unknown whether being frozen is necessary to undergo cold sleep) and has therefore been asleep like this for 800 years until the events of Light Novel Volume 5.
As the Siren Empress, Laira is able to mate and reproduce with a male without killing him. In fact, she is so fertile that she's able to reproduce with the soul essence found in a single lock of male hair.
Although Sirens are never known to be smart, she is probably the least intelligent character introduced to date. Her naïve belief in a fairy tale singlehandedly drove both the Siren and Dhampir race to the brink of extinction, not to mention the winning condition of her game is practically unachievable due to her extremely strong innate attraction. She pissed off everyone so much, even her fellow Siren rejoiced when she was getting abused in her dream.
Due to her incompetence, Sora and Co. never get her to participate in any games during their conquest. During the Sugoroku game, her contribution was to lend Sora her Race Piece and act as the bargaining chip to force Plum into unconditioned cooperation.
Besides intelligence, she has the general Siren weakness of inability to survive without water. Since Plum was feeding on her blood, she would also be inflicted with the vampiric disease and become weak against sunlight.
- Due to her immense fertility as the Siren Empress, she is able to reproduce even from the minute amount of soul essence found within a single lock of a male's hair. This is the case in which Sora and Laira now have a daughter despite having no sexual intercourse and within a very short gestation period.
- Laira actually showed up physically as a cameo during the end of No Game No Life: Zero: her tail fins was poking out of the bag carried by Steph. This is alluding to the events in Volume 8.