Sitri

Sitri is one of the two demons sent by Beelzebub to capture the Special Children. He is the brother of the demon, Gremory. Like his sister, he resurfaced shortly after the defeat of Trihexa. Under Beelzebub's orders, Sitri infiltrated the Azazel Cup under the alias, Seth.

Appearance
Sitri, in his human form, is a handsome young man with spiky red hair and red eyes. His eyes shift to black and green when his powers are active.

Sitri is commonly seen wearing red armor with a giant violet gem in the middle. In his true form, Sitri is a massive red demonic being with green eyes and four leathery bat like wings.

Personality
Sitri is lazy despite being one of Hell's top operatives. He is also highly sadistic and a glutton often toying with his prey before inevitably eating them out of amusement. Like his sister, Sitri is vengeful and was eager to pay Issei and Eden Squad back for their first battle in Tokyo.

Sitri, despite his laziness, is an effective agent. He is very loyal to Beelzebub and the Firstborn not wanting to anger or fail them in any way.

Powers and Abilities
Sitri is an extremely powerful demon sent by Beelzebub. Stated by Blacklight to be one of Hell's top operatives, Issei felt Sitri's Miasma signature from several miles during the Azazel Cup Finals. Back during the first battle in Tokyo, it was revealed that Sitri was holding back an immense amount of power rendering his previous GPS Ranking wrong.
 * Immense Strength: Sitri has immense levels of raw physical strength. He was able to block Gram easily and even the force of his swings sent Vali's peerage, the Gremory Peerage, Bael Peerage, Sitri Peerage, and Eden Squad flying with a single swing.
 * Immense Durability: Sitri is extremely durable being able to withstand one of Ingvild's strongest spells and a blow from Risa.
 * Immense Speed: Sitri is extremely fast.
 * Advanced Telekinesis: Sitri can move and influence matter with his mind. He was able to pin all the young devils in addition to Vali Team and Eden Squad just by raising his palm.
 * Advanced Umbrakinesis: Sitri can control and generate darkness like other demons. He is able to create an energy arc with his halberd that was described by Rossweisse to have been able to "split the sea in half". Sitri can also fire energy blasts made of pure darkness.
 * Electromagnetic Interference: Sitri's mere presence can cause technology to go haywire even those enhanced by magic.
 * Teleportation: Sitri can teleport.
 * Flight: Sitri is capable of flight.
 * Master Halberd Wielder: Sitri is an expert at wielding the halberd being able to fight Risa on even ground with just his halberd.
 * Master Hand to Hand Combatant: Sitri is a master at close combat. He was able to fight Rossweisse, Kiba, Gasper, and Ingvild without showcasing much of his powers other than flight and minor Umbrakinesis.
 * Invulnerability: As a Demon, Sitri cannot be harmed by conventional weaponry such as guns. He is also immune to most of the weaknesses of devils such as light. Only Enochian Weapons or beings of similar or greater power can kill him.
 * Immunity: Sitri is immune to nearly all devil weaknesses including light and holy swords. He is also immune to most poisons and diseases that exist in Creation.
 * Advanced Regeneration: Sitri has an advanced healing factor being able to heal wounds that would kill most other beings.
 * Immortality: Sitri has existed since nearly the dawn of the Solar System.

Weaknesses

 * Higher Level Beings: Sitri fears Beelzebub's power but most of all, he fears the Firstborn.
 * Enochian Weapons: As stated by Azrael, Sitri, like other demons, can be killed by Enochian weapons.
 * Exorcism: Sitri was exorcised by Eric Marshall during the Battle of Sioux Falls.

Trivia

 * Sitri's human form is based on L'Arc from Tate No Yuusha No Nariagari. His true form and armor are based on Galand from Nanatsu no Taizai.
 * Gremory and Sitri's dynamic is mostly based on the relationship between Rias and Sona. Both Gremories share a close relationship with their Sitri counterparts. Both Gremory and Sona are often exasperated by the antics of their sibling/friend. For Gremory, it's Sitri's habits and for Sona, it's Rias's tendency to attract trouble.