Geelan

Geelan (ギーラン) is a character of The Promised Neverland series. He was the lord of the Geelan Clan and previously a demon noble who once advised the royal family and nobility. However, the royal family and the other Five Regent Houses then betrayed and framed him for treason, and consequently purged Geelan and his clan.

Ever since then, Geelan harbored great hatred towards the royal family and desired to get his revenge on them, which he later did during his clan and "William Minerva"'s surprise attack during the Tifari held at the Imperial City, where the royal family and the members of the regent houses were. However, he met his end by the hands' of Queen Legravalima towards the end of the battle.

History
Seven hundred years ago, Geelan was a noble and honorable demon who tried to find peaceful solutions to problems regarding the overpopulation and the quality of the human meat. He was the only member who advocated for the good of the lower masses and tried to convince his fellow heads to provide the people with high-quality meat from their stocks to prevent starvation.

However, this caused him to become ostracized by his former peers. Additionally, Queen Legravalima loathed this idea, and because his morals were viewed to be inconvenient and opposed to the Queen's view on the situation, she and the other five regent families left him and his clan to rot in the wastelands as punishment for his noble intentions. Because they were not able to consume human flesh during the time period of 700 years, Geelan's clan was forced to eat each other as to not degenerate to wild demons. The time came where Geelan had degenerated to a wild demon, but his former, loyal followers willingly offered themselves so he could revenge on the Royal Family for them.

Ever since then, Geelen has waited for the day he could get revenge on Legravalima and the other royals.

Appearance
Geelan was described as being beautiful and noble when he was still the head of one of the families, but years of starvation had mutated him into a more bestial form. He possessed a hideous insect-like appearance along with an imposing figure, towering over Norman. He appeared to be adorned with several garments. After consuming the head of the recently decapitated Lord Pupo, Geelan took the form of an in-between state from his original and then-current monstrous appearances.

Personality
Geelan used to be a very kindhearted, righteous, and noble demon who thought about the well being of his people as much as the royals. He spoke up for what he believed in, and advocated for the things that would benefit as many people as possible. He was also loyal to those he trusted, and prioritized keeping them safe. However, after the Royal Family banished him, causing him to devolve into his more bestial form, he became much more ruthless and vengeful. For the past 700 years, it was his murderous hatred against the royal family that drove him to achieve his lethal goals. Though his primary targets were nobles and royalty who betrayed him, he now was more tolerant of cruel and ignoble actions like killing innocent juvenile demons. Still, he maintained his rationality, responsibility, fierce loyalty and protectiveness towards his clan.

Imperial Capital Battle Arc
He teams up with Norman in his plan to attack the Imperial Capital, starting the Imperial Capital Battle, in order to enact revenge for his exile. During this battle, he kills many demon nobles before he is killed by Legravalima after attempting to kill her.

Norman
Norman, who took up the name of the deceased William Minerva, formed a temporary alliance with Geelan and his clan. Both of them display antagonism towards the royal demon family and the five regent houses, and thus they are on neutral terms with each other and view each other as allies for the current time being. Norman promises to aid Geelan in getting revenge on the royal family and the houses in exchange for freeing the orphans in the farms the demons own. Though the two agreed on the said terms, both sides are skeptical of trusting each other and both planned on backstabbing the other once their side of the promise is fulfilled.

Geelan heavily suspects Norman's intentions, and does not believe him to be the actual William Minerva due to the news of how the latter has died. Geelan theorized Norman to be one of the escaped premium quality child from Grace Field House due to his young, physical outlook. From which it sparked his intentions of consuming him, as shown when he licked Norman's bloody fingerprint which was inked on his contract with him.

Legravalima
Geelan loathes the royal demon family due to how they had betrayed him and his kind. It was not shown whether Geelan hated Legravalima in particular, but most likely should since she is part of the royal family.

Trivia

 * Geelan's favorite food is human.