Jibril

Jibril (ジブリール) is the youngest and strongest of the Flügel race. Her love toward knowledge started even before the declaration of the Ten Oaths. She is against the book sharing law, and left her homeland to win the National Library of Elchea from the previous king in a game. When Sora heard what happened to the library, he challenged Jibril in order to gain knowledge of the other kingdoms. When she lost the game, she became Sora and Shiro's servant since she had bet everything she owned, including herself, claiming that knowledge was worth her own life. Jibril thus took Sora as her master and over time she began to understand and accept Sora's belief in the potential of humans. Unlike Steph, Jibril is happy to become the siblings' underling, and is shown to have grown feelings toward Sora.

According to Azriel, Jibril was given the gift of imperfection by Artosh. This gift is what Artosh believed would allow Jibril to find the answer to the Flügels' continued existence.

Appearance
She has long purple-pink hair, wings near her hip. Her pupils become cross shaped when she is focusing for a task (such as performing a spell) and her ears are wing-shaped, she also has a halo over her head. She usually has her midriff exposed and wears a long skirt.

Personality
She seems to be soft spoken and polite, but she can also be incredibly condescending to other races, as shown when she indirectly insults Stephanie Dola and when she refuses to apologize to Fiel Nirvalen for wrecking havoc, also when told she had to lick Fiel's feet she refused saying she would not lick a 'mere' elf's foot. She has a great love for knowledge and gets easily excited at the prospect of gaining new knowledge, such as when she drooled over Sora's tablet after seeing the vast information it contained. Despite her initial arrogance, she has a high sense of honor while playing games, as she doesn't like cheating, or being cheated. She tends to remember the "good old " days, before the oaths were established, when everything could be solved by killing, in a rather disturbing way, somewhat showing her sadistic personality. Unlike Steph, Jibril fully embraces her servitude to Sora and Shiro, going so far as addressing them both as "Master." Throughout the anime and light novel, Jibril's feelings for Sora seem to grow, despite stating she's not supposed to have the feeling called love. Jibril first stated her feelings in Episode 10 wondering even though it's supposed to be humiliating that she licked Fi's foot, if she takes it as a order from the master she gets excited, questioning whether it could be love, before Sora interrupted her. Despite this, in Volume 4 Jibril has expressed a willingness to merge a part of Sora's soul with her own to attempt to create a hybrid, essentially showing a willingness to bear his child. Later on, in Volume 5, she confesses to Sora that she can finally understand love and has also fallen in love.

History
Jibril was the last Flugel created by the Old Deus Artosh and served under him until his demise. During the war of the gods she destroyed the capital of Elven Garde with a single spell, called "Heaven's Strike," which resulted in Jibril not being able to use magic for 5 years. Afterwards Jibril stole all the books in Elven Garde despite the Elves best attempts to prevent this. Due to the loss of so many books, the Elves lost a considerable amount of magic and as stated by Fii, it took over 800 years to regain all the lost powers.

Sometime during the Great War, while embarking on one of her solo campaigns, she came across an Exmachina named Shuvi. Exmachina heads were extremely rare prizes amongst the Flugel, because at the time there was an unspoken rule to never provoke the Exmachina lest one seeks ruin. However, Jibril was confident she could take down Shuvi, so she had no choice but to retaliate. Despite her greatest efforts, Shuvi was ultimately defeated and killed by Jibril. However, Jibril did not escape unscathed, as she had used Heaven's Strike against Shuvi and lost all of her magic power.

After Artosh was defeated and the war concluded, Jibril lived in the Flugel city Avant Heim for some time. However with the passage of the Book-Sharing Law, she decided to leave as she did not agree with it and did not want her books passed along freely. Sometime after she challenged the Imanity King for the rights to his library, which she easily won. Jibril then stayed at her library until being challenged by Sora and Shiro, where she lost in a game of Materialization Shiritori. In accordance with the bets for the game, she swore her very being to Sora and Shiro. Although not requested by Sora and Shiro, Jibril would go on to accept the siblings as her new masters, seemingly having replaced Artosh.

Jibril would then follow the siblings on their quest to reach Tet, the one and only God. This included helping them in their quest to acquire the Werebeast nation, Dhampir and Seiren Nation, and even a trip to her homeland, Avant Heim. Along the way, she has been documenting their actions to be recorded down in her own book.

Strengths
As the final unit and most powerful individual of the Flügel race, her massive strength was hinted at by Azrael who stated that, were she to assist Sora and Shiro in playing a game of tag against 100 other Flügel, the match wouldn't be considered a competition at all. It is unknown what her full capabilities are (disregarding Heaven's Strike) however, parting a pathway through the sea to Oceande is apparently a representation of 5% of her full strength.

The knowledge she has gathered during her millennia of existence are incredibly vast. She's also a very competent mage, capable of using spells to teleport herself, Sora, Shiro and Steph to any place she can see or that she's been to previously. She's also capable of phasing through walls at will.

It is said that Jibril has once used a spell called "Heaven's Strike," also called "Airstrike," which had completely anhilated the capital of Elven Garde. As a drawback, she could not use any magic for 5 years. In Volume 5 of the novels she uses the power again but does not suffer from any recoil as she was in an illusionary world where her magic power was unlimited.

Weaknesses
Due to being a Flügel, Jibril is very dismissive of other races below her own and her confidence in her own knowledge. This in turn causes her to overlook the potential threat posed by the said races. This is no more evident than in her game with the siblings, that even with the knowledge from her examination of Sora (that the siblings weren't from Disboard), she still regarded Sora and Shiro with barely concealed scorn, but was intrigued by the discovery.

Sora mentioned that Jibril lost in her game of Materialization Shiritori because of her arrogance. For example, the game could have ended in Jibril's favour in the first move where Sora and Shiro called upon a Hydrogen Bomb. Instead Jibril shielded them from the blast because, as Sora predicted, it would have been boring for her.

Trivia

 * While the name Jibril has been noted to be an Arabic reading of Gabriel, the author stated that Jibril was not related to the figure.
 * As the "final unit" of the Flugel, Jibril's power is capable enough to kill a Gigant, a Dragonia, and a Phantasma on separate solo campaigns. However, her failed attempts to do so were twenty nine times more (simply put: out of 90 attempts, 3 were successful).
 * Whenever Jibril uses Heaven's Strike, her body regresses to that of a young girl.