Eugeo

was the deuteragonist of the first half of the Alicization Arc in the Sword Art Online series.

Background
Eugeo was a child born in a remote village in the Human Empire of Underworld, where he was assigned the Sacred Task of felling a giant tree with his childhood friend Kirito. After a mishap during an adventure to the mountains resulted in his other childhood friend Alice Zuberg being apprehended by an Integrity Knight for breaking the Taboo Index, while his memories of Kirito were sealed by the administrators of the world, Eugeo spent the following six years focusing on his work to avoid thinking about his lost friend, until Kirito's return to Underworld led to Eugeo building the resolve to embark on a journey to become an Integrity Knight himself to rescue Alice, as well as acquiring the skills to wield the Blue Rose Sword he had retrieved from the mountains where Alice had broken the Taboo Index.

One year later, Eugeo and his partner Kirito successfully enrolled at the Sword Mastery Academy as one of the top twelve students of the year, thus becoming a valet to Elite Disciple Golgorosso Balto. As the fifth best student at the end of the first academy year, Eugeo became one of the twelve Elite Disciples the following year, being assigned Tiese Shtolienen as his valet. However, when his valet Tiese and her friend Ronye Arabel were provoked by high-ranked nobles Raios Antinous and Humbert Zizek into insulting them, Eugeo overwhelmed his Seal of the Right Eye and broke the Taboo Index by slashing Humbert in an effort to save the girls from being sexually abused by the high-ranked nobles, leading to Kirito also breaking the Taboo Index by attacking Raios to save Eugeo from retribution.

Branded as criminals, Eugeo and Kirito were arrested and brought to a prison at the Central Cathedral of the Axiom Church by Integrity Knight Alice Synthesis Thirty, Eugeo's former childhood friend, who no longer had any recollections of her past. After escaping the prison and learning the truth of the world from Cardinal, the duo fought their way to the top of the Cathedral to acquire Alice's lost memories and defeat the ruler of the Axiom Church. During the final battle against Quinella, the Supreme Priest of the church, Eugeo merged with Alice's lost memory fragment and his sword in order to defeat Quinella's Sword Golem, but suffered fatal injuries when he attacked Quinella after defeating the golem, passing away in the aftermath of the battle.

Appearance
Eugeo was described as a slender-looking boy with soft-looking flax-brown, slightly wavy hair, green eyes and a cream color skin. Before getting accepted into the Sword Mastery Academy, he wore the same unbleached, rough cotton or flax, short-sleeved, light blue tunic with irregular texture, hand-sewn threads on the cuffs and a V-shape cut on the chest, tied with a light brown cord, and trousers as Kirito.

When Eugeo joined the Academy, he wore a standard grey uniform. After becoming an Elite Swordsman-in-Training and being given the privilege to customize the color of his uniform, Eugeo chose to wear a blue and gray uniform.

Upon escaping from the prison in the cathedral, Eugeo, along with Kirito, stumbled upon a room filled with weapons and armor, along with a set of clean clothing. Using the opportunity, Eugeo changed his torn and damaged Academy uniform into a blue outfit made from the highest quality materials.

After Eugeo was converted into an Integrity Knight, he temporarily wore an elegant bluish and silvery white armor with a cape.

Skills

 * Aincrad Style
 * Horizontal
 * Vertical
 * Vertical Arc
 * Sonic Leap
 * Meteor Break
 * Slant (Self-Discovered)
 * Balto Style
 * Head Sea

Equipment

 * Project Alicization
 * Blue Rose Sword: Eugeo's main one-handed sword
 * Armament Full Control allows the sword to cover the area in ice and then entangle in pinky-thick thorny ice tendrills than freeze on impact.
 * Dragon Bone Axe: Axe used to cut down Gigas Cedar.
 * Unnamed Spirit Iron Chain

Trivia

 * Eugeo is voiced by Nobunaga Shimazaki in the anime adaptation of Sword Art Online.
 * He shares a voice actor with: Kunimitsu Shidou (Eromanga-sensei), Tetsuhiko Kai (OsaMake), Orbas (Shakugan no Shana), Ollerus (A Certain Magical Index).