|“||—I will show all of the forces what “Devils” are by using Rizevim. I will make them realise it. I want them to realise just how brutal and dangerous the evil species called “Devils” are. For me, I don’t care about ruling and politics. No, that is the same for Rizevim-sama. —At the final stage, I want to show what “Devils” are to the human world as well.||”|
Euclid Lucifuge is the younger brother of Grayfia Lucifuge, the uncle of Millicas Gremory and the brother-in-law of Sirzechs Lucifer. He was a member of Khaos Brigade's Qlippoth, being the leader of the Magician Faction Nilrem, and was considered as Rizevim Livan Lucifer's right arm.
Euclid is a young handsome looking man appearing in his early twenties with silver hair that is tied in a braided hairstyle. He wears a silver robe with detailed accessories.
Euclid is a calm and collective individual with a ruthless and manipulative side to him as well. Due to his upbringing as a Lucifuge, Euclid is a fanatic Lucifer loyalist, with narrow-minded loyalty to the original Lucifer. Euclid fully supported the original Lucifer's ambition and ideas of world domination and unlike his sister, he is unable to accept the pacifistic rule of the current Satans, as he completely despised the current Satans particularly Sirzechs for upsurping Lucifer's rulership over the Devils. Euclid's loyalty to Lucifer also extends to his son Rizevim Livan Lucifer, as it was Rizevim's lineage as Lucifer's son that drove him to join Qlippoth and commit terrorism solely out of blind loyalty. Euclid also adopted Rizevim's ideals of what a "Devil" should be, believing that it is their job to be evil, manipulative, brutal and ruthless. He even claims that his reason for joining Rizevim is solely for the sake of proving to other mythological factions that Devils are the most brutal species.
Euclid is shown to be completely obsessed with his sister Grayfia, going as far as to create a Replica of a Boosted Gear which is "Red" in order to become similar to Sirzechs, who is also "Red". His obsession with Grayfia is so extreme that he wanted to make Rossweisse his "sister" due to their similarities. This obsession, however, combined with his fanatic loyalty to the Satan Lucifer, also created tremendous disdain towards Grayfia for abandoning her role as a Lucifuge by defecting to the Anti-Satan Faction. He even went as far as to say that she 'went so low as to become a servant of the Gremory', referring to Grayfia's position as the Queen of Sirzechs who came from the Gremory clan.
In Volume 17, it was revealed that, for countless years, Euclid was emotionally torn between his love towards his sister and his personal dedication to his duties as a Lucifuge. Due to Grayfia defecting from the Old Satan Faction and betraying Lucifer, an act which Euclid considered to be atrocious as a member of the Lucifuge Clan, Euclid felt tremendous despair by his sister's betrayal and became immensely nihilistic, no longer taking interest and value in anything, only desiring to create and experience chaos. To this end, Euclid willingly followed and supported Rizevim in committing many atrocities, such as becoming a terrorist, causing tremendous damage and chaos to the Vampires' homeland, as well as launching an assault on Auros Academy, endangering the lives of innocent people and destroying parts of Auros Academy simply to spite Rias and Issei, showing utterly no remorse for his actions.
Like his sister, Euclid came from the noble House of Lucifuge and was also a part of the Old Satan Faction. In his youth, Euclid dearly loved his sister and admired Grayfia for her courage and strength as one of the strongest Devils of the Old Satan Faction. After Grayfia fell in love with Sirzechs and defected from the Old Satan Faction, effectively betraying the ideas of the Original Lucifer whom the Lucifuge Clan had sworn to loyally serve for generations, Euclid fell into despair and was completely heartbroken by his sister's betrayal. For centuries, Euclid was emotionally torn between strong familial love and intense anger toward Grayfia. When Euclid went missing after the Old Satan Faction lost to the Anti-Satan Faction, he was presumed dead by many, including his older sister. At some point in time, he met Rizevim and told him about Ophis' stolen power, the Holy Grail, the proof about the other world, and 666 (Trihexa).
Power and Abilities
Immense Demonic Power: Although, he has yet to demonstrate his full powers, Azazel mentioned that he could lead the Khaos Brigade himself. Due to his aura being similar to his older sister, he was allowed to bypass Kuoh Academy's barriers and let the Nilrem and Hexennacht Magicians without being detected. Euclid stated that his power was equal to his older sister Grayfia, who is said to have Satan-Class power. However, Issei later concluded that Euclid was weaker then Grayfia due to being a "shallow existence".
- Dragon Shot (魔力弾, Doragon Shotto): Issei's signature move that was copied by Euclid, along with the Replica Boosted Gear. Euclid fires a blast of concentrated energy from his hand that's been enhanced by his Boosted Gear. Unlike Issei's Dragon Shot, Euclid's version is a mixture of red and silver. Euclid's Dragon Shot enhanced by the Boost ability is comparable to Issei's Crimson Blaster, as the two attacks canceled each other out when they collided.
Immense Strength: Euclid has immense strength, strengthened from using the Scale Mail allowed him to almost overpower Issei in his Crimson Armor; stopping his Solid Impact Booster head-on, then breaking his armor using a punch at almost the same moment. Issei even noted that Euclid was using the power of the Red Dragon Emperor better than him despite being a replica without Ddraig, as he negated Issei's Crimson Blaster using a Boosted Dragon Shot.
Immense Durability: Euclid demonstrated immense durability, as it took Issei using his Dividing Wyvern Fairies to reflect a barrage of his Dragon Shots at Euclid's weak-points and then a barrage of barrage of Boosted Dragon Shots to wear him down so Issei could fully finish him with Longinus Smasher.
Expert Magician: Euclid has shown to be highly proficient in magic, as he could bypass the barriers protecting Kuoh Academy and allow Stray Magicians to sneak in without detection. He is also skilled in other types of magic such as teleportation.
- Teleportation Magic: He can also use transportation magic, demonstrated when he summoned Grendel and sent him to Vali far away.
- Explosion Magic: Euclid can implant explosive spells inside the bodies of the Stray Magicians who infiltrated Auros Academy and set them to detonate when he needed.
Master Inventor: Through his own methods and using the Sephiroth Graal to collect information from fragments of Issei's flesh from his old body, which contained information regarding Boosted Gear and Ddraig's soul. He was able to create a Boosted Gear Replica, something that not even Azazel, the Leading expert in Sacred Gears was able to achieve as stated by Ddraig, however it required the souls of famous Dragons to use each time.
Flight: Being a Devil, Euclid can fly using his wings.
Boosted Gear Replica (Formerly): Euclid was able to create a replica of Boosted Gear by collecting information of the Red Dragon Emperor's soul and the Sacred Gear from Issei's original body left in the Dimensional Gap by using the Holy Grail. Unlike the original Boosted Gear, Euclid's Boosted Gear appears on the right hand with silver lining. While its potential is weaker than the original, Euclid demonstrated exceptional mastery of it to the point that he surpassed Issei, who uses the original Boosted Gear. Even Ddraig admitted Euclid can bring out the Red Dragon Emperor's power to the maximum. The Sacred Gear has a program that destroys itself if Euclid should ever be defeated, which it did after his loss to Issei in Volume 17.
- Boosted Gear Scale Mail: Euclid is able to use the Balance Breaker of the Boosted Gear by sacrificing the souls of several famous Dragons since he was unable to make a copy of Ddraig's soul. The armor looks like Issei's Scale Mail, albeit with slight variations. Like the Balance Breaker of the original Boosted Gear, Euclid can multiply his power any number of times he wishes, but at the cost of a large amount of his stamina and demonic powers. During his short fight with Issei Hyoudou in Volume 16, Euclid was able to overwhelm Issei with minimal effort in this form despite the fact that Issei was using his Cardinal Crimson Promotion, and it amplified his durability to the point he could survive taking Issei's Longinus Smasher head-on, albeit in a severly injured state with blood coming out from his whole body.
- Euclid held hatred towards Sirzechs for his existence as a Super Devil, as well as having Grayfia's love and affection. Ironically, just like Sirzechs, Euclid has an immense sister complex.
- Euclid may have been named after the Greek mathematician Euclid of Alexandria due to both of them being master inventors.
- Light Novel Volume 17, Life.4 The Youth Devil