Tenebris

Tenebris is the main antagonist of Final Fantasy XVI. He is the younger brother of Delia Asmius. His primary goal is to reduce the world into nothingness.

Personality
Tenebris is a very simple man who expresses himself without much thought. He is best described to act like a child without much understanding of the universe or why people act the way they do. Because he cannot speak, frustration grows inside him whenever he is unable to express himself successfully.

Often times, when others attempt to control Tenebris's emotions by explaining things or giving orders to him, he follows them without needing much clarity or reasoning behind. He has no set of morals or restrictions that enable him to stop and think. Tenebris is also a very blatant and physical person. He believes that all problems can be solved with violence or death.

Before the Cycle of Corruption began, Tenebris was an intelligent man and became one of the many worshippers of Bahamut and the espers of Olion. Even in the past, he still showed vital characteristics of his present self by thinking irrationally and acting impulsively.

Once an advocate for world peace, his mind was driven into insanity after meeting Enkidu, a corrupted demigod at war with the espers. He sided with the darkness and eventually corrupted himself, destroying Olion and himself but maintaining his spirit in the afterlife. After the espers created multiple universes to restore the planet, Tenebris lives on to seek a way to destroy everything, as he sees all life as meaningless.

Appearance
Tenebris is a tall man that stands at 188 cm (6'2") with short silver hair and crimson red eyes. He is shirtless and wears black tight belted pants. He has black colored tattoos that depict Enkidu's tribal appearance. He also wears spiked gloves on both of his hands. Because he is a humanoid, his rebirth gives him extremely false appearing pale skin and a perfect complexion to his face, making him appear handsome.

Abilities
Tenebris's abilities are inexplicably powerful to the point that even the espers fear him. His most notable ability is the ability to possess others like a parasite without having a stable body. While possessed, he can mimic and act much like their host without risk of being caught. He can even permanently migrate his soul into his host's body to take over them permanently, resulting in their death in the process.

After his new birth, Tenebris is still capable of such abilities but must escape from his own body as a result. His combat abilities are rather simplistic. He uses a mixture of close combat and harnesses the power of Ultima in order to infuse his attacks in many ways to increase havoc. He can also harden his skin to feel no pain and further increase his vitality. He can also warp around the area, much like June can but with the power of Ultima.

Story
Spoiler warning: Plot and/or ending details follow.

Prologue
Tenebris was born as the first-ever male in the universe, nicknamed as Olion's Adam. In M.E. 1, he was created along with Delia Asmius by Eden, and the two were made to become siblings in order to combat the evil Enkidu during the first Cycle of Corruption. As Tenebris grew up with his sister, the Darkfire intrigued him to no avail, hoping that he could acquire such a degree of power. His relationship with Delia was riddled with jealousy, and she purposely ignored him because of his observant and rash behavior.

Tenebris began living his life as a devoted esper worshipper, reading and studying about their legendary powers and their origins. His relationship with his sister began to worsen as she began holding a large number of responsibilities as the first light of Olion. She gradually distanced herself away from him, and as a result, Tenebris began holding a childish grudge against her after wishing he could join her on her adventures.

With his lust slowly drawn to become better than his own sister, Tenebris gradually sought new methods in order to obtain supernatural powers to prove his own sister wrong about his childish behavior. He founded a group known as the Scholars of the Espers, which were fanatics about researching the history or the espers and ultimately any methods of ascending to their degree of power. Eventually, after his acts and deeds in Elzil were considered inhumane and a disturbance to the public, the citizens eventually exiled him without his sister's help, causing him to become homeless in the process.

After his exile, Tenebris slowly became insane without a proper direction. His jealousy for his sister only increased his anger, causing him to grow madder over time. Soon after his exile, Tenebris was visited by Enkidu, a corrupt demigod who hoped to ascend to the levels of the esper's power so that he may dictate the rules, laws, and composition of Olion as a whole. Enkidu lies to Tenebris and tells him that the espers are the enemies and that they seek Enkidu's power as a result of jealousy. He explains that he has done nothing wrong to harm the planet, whereas Tenebris believes him because of his undying lust for power. Enkidu chooses Tenebris as his apprentice in order to stop Gilgamesh, the guardian of the Asmius family. Tenebris believes that Enkidu's act of choosing him as an apprentice meant that him worshipping the espers would soon grant him the power he desired to prove Delia wrong.

Over time, Tenebris was persuaded by Enkidu to perform carnal deeds across Olion in order to draw Gilgamesh out from hiding. Eventually, when Gilgamesh finally arrived to stop Tenebris and Enkidu, Tenebris baits himself as a helpless civilian begging for help, baiting him into Enkidu's trap and stealing his powers from him. As Enkidu reveals himself as Gilgamesh's brother, Tenebris begins to feel like a slave rather than an apprentice, causing him to feel worthless.

When Delia arrives after identifying Enkidu as the source of darkness in Olion, Enkidu merges himself with Tenebris and the two battle. He murders his own sister Delia, but a safe fail tactic under her sleeves causes Tenebris to also become destroyed.

Even though his body was destroyed, Tenebris's spirit, merged with Enkidu, was alive in the crystalline world where the espers ventured off to. He possessed all of the espers and sealed them to prevent them from using their powers permanently, but as a result, Tenebris loses his body and his ability to speak or think properly. He would then attempt to travel to the worlds without a body, corrupting and possessing multiple influential people in order to help achieve immortality while subsequently using his powers to keep the espers at bay. The espers use their powers in order to fashion multiple worlds as they cannot die, in order to create new versions of daughters to the Asmius family order to defeat Tenebris. Tenebris begins to live out multiple cycles of the same universe but cannot seem to succeed in retrieving his body and ruling the world on his own.

Final Fantasy XVI
In M.E. 701, Tenebris returns in Olion as the host of Chance Williams in the sixth Olion. The time it had taken for him to finally attain a new body had finally been met after growing inside Chance's body, and when June and the party first encounter him on Baron's sky cruiser, Chance vomited the celestial being out from his own stomach. A nude Tenebris emerges from Chance's body, finally given the birth of the perfect deity with an unnatural possession of strength. However, after recklessly using his powers to seal the espers, Tenebris loses the ability to speak or convey any emotions until he is rejoined with his other half, Enkidu, who also exists in Olion in M.E. 701.

After using his powers to murder Chance on the spot with body combustion, Tenebris becomes adorned with part of Chance's clothes while escaping. During this time, Tenebris rejoins with his other half, Shern, who has been housing Enkidu's soul secretly. The two of them devise a new plan to use June Asmius, the light of Olion at the time, to steal her powers so that they may become the most powerful in the universe. Tenebris seeks to do this under Shern's request, forgetting almost everything in his past like a madman.

When June learns of the truth behind the story of the Sixth Olion, she encounters Tenebris and Shern who claim to have been watching her this time, explaining their motives.

After Baron's defeat, Tenebris possesses him and murders him under Shern's direct orders, along with Gistal. After seeing June's face, anger builds up inside him and he possesses Mari Emilia, taking control of her and also causing her to combust, murdering her on the spot to enrage June. He is killed by June but is still immortal as his body exists in the crystalline world. He escapes in a new body and later on regroups with Shern in order to destroy the universe. Tenebris eventually travels to Galacye to murder Vizian Izara, along with Queen Lidia Nibleheim and Elizabeth to further enrage June.

Tenebris and Shern capture June and Jill aboard a train to Elzil. Shern kills June and Jill leaps for her outside of the train when she is tossed off while Tenebris witnesses it and laughs.

At the edge of Elzil, June battles Shern and Tenebris with a plan to use Asura's nethicite to trap Tenebris and the two of them travel back to M.E. 1. A long ensuing fight begins with June failing to match Tenebris's chaotic strength. When June's friends arrive to assist her, Tenebris merges with Shern in order to morph into a hulking manifestation of Humbaba known as Zei. After defeating Zei, Shern is destroyed and Tenebris fails to merge with his other half.

June uses Asura's nethicite to warp Tenebris, Jill, and her back to M.E.1 in First Olion, rendering him vulnerable because of him returning to his original timeline. Tenebris then exhibits his ability to speak his mind, telling June that the world is meaningless and deserves to be destroyed for the pain it caused him. He goes off to tell her that the Asmius family only made him afraid for who he was, referencing to his sister Delia, to which June responds with how life is always unfair. He goes berserk, using his full strength in order to kill June and Jill to end the Asmius lineage, but is defeated after June begins to scare his childish instincts with the concept of hope. Tenebris is permanently killed by Jill with a stab from her blade, causing June's present world to be changed drastically.

However, Tenebris's soul would then be absorbed by Vizian, which is destroyed later when June defeats him.