Byleth

"I will return here someday my teacher, promise me that you won't forget me."

- Edelgard talking to Byleth

Byleth, is a playable character and the main protagonist in Fire Emblem: Three Houses. As an Avatar, their name, gender, and birthday are chosen by the player. In voiced cutscenes, they are referred to as Professor. They possess the mysterious Crest of Flames and can wield the Sword of the Creator. They do not have a confirmed age, with it being listed as "???" in various menus.

Profile
Byleth grew up among mercenaries led by their father, Jeralt Eisner, and their mother died shortly after they were born. Among their father's mercenaries they earned a fearsome reputation as a warrior known as the "Ashen Human/Demon/God."

Byleth's mother bore the Crest of Flames, which manifested in her heart. Upon giving birth to Byleth, their heart did not beat. Desperate to save her child, she begged Rhea to transfer her Crest Stone into Byleth, reviving them but also losing her life in the process.

In recent times, Byleth has been having dreams of a young green-haired girl, however when they inquire with Jeralt, he does not know anyone by the same description. Jeralt reminds Byleth that their next job will bring them to kingdom, but a sudden uproar occurs when three students from the Officer's Academy, Edelgard, Dimitri, and Claude approach the two, asking for their assistance with some bandits trying to kill and plunder the trio With Byleth and Geralt's help, most of the bandits are dispatched, save for their leader Kostas who attempts to attack Edelgard, forcing Byleth to step in between her and his Axe. Just as Byleth is about to be struck, time freezes and Byleth encounters the green-haired girl once more who chastises them for being reckless. Introducing herself as Sothis, a name she just recalled, she and Byleth realize that they can rewind time so they can prevent Byleth's impending demise. The flow of time reverses and Byleth is able to not only push Edelgard out of the way, but also disarm Kostas, quelling the remaining bandits.

Reinforcements arrive from the Knights of Seiros shortly afterwards and one of its members, Alois, recognizes Jeralt. He invites the two to visit Garreg Mach Monastery and they comply. Before departing, Byleth converses with the trio from earlier, each impressed by their skill. They extend invitations to join the service of their respective kingdoms and Byleth expresses interest in one of them. Given the journeey ahead, the trio get to know Byleth in order to sway them over to their side.

After saving Officer's Academy students from bandits reveals the Crest of Flames within Byleth, they are offered a position to teach at Garreg Mach Monastery's Officer's Academy by Archbishop Rhea of the Church of Seiros due to Alois' recommendation. Byleth also begins to communicate with Sothis, a mysterious girl with no memory of her past. Previously they had only seen Sothis in their dreams.

Byleth becomes the teacher of one of the three student houses of the Academy: the Black Eagles, Blue Lions, or Golden Deer. As part of their training, Byleth at times leads their students into live combat.

Byleth specializes in swords and uses the Sword of the Creator as their primary weapon.

Personality
Byleth has a very subdued personality and has difficulty expressing emotion. However, people they are especially close to, such as Jeralt, are able to tell how they're feeling.

Overall
Given their skill levels, Byleth will have easy access to the Myrmidon class family (Myrmidon, Mercenary, Thief, Swordmaster, Assassin), the Soldier class family (Soldier), the Fighter class family (Fighter, Archer, Brawler, Sniper, Grappler), and the Monk class family (Monk, Priest, Bishop), as well as their exclusive story-based promotion, Enlightened One.

Supports
Like previous Avatars, Byleth is able to form supports with every character in game, including both Rhea and Sothis who are only able to support with them. They are also the only character in-game that is able to form an S-Support with their partner. Each gender of Byleth is able to S-Support with all characters of the opposite gender. Male Byleth can form a same-sex S-Support with Linhardt, Gilbert, and Alois. Female Byleth can do the same with Edelgard, Dorothea, Mercedes, Sothis, and Rhea.

Three Houses

 * Byleth/Quotes

Heroes

 * Byleth/Heroes Quotes

Fire Emblem 0 (Cipher)
Byleth is illustrated in the trading card game Fire Emblem Cipher with the following cards:

Possible Endings
Byleth - Wandering Flame
 * Byleth defeated those who slither in the dark and put down the crazed Immaculate One. In the aftermath of the loss of Fódlan's great leading figures, he/she ascended the throne as the first leader of the United Kingdom of Fódlan. In his/her heart lived the indelible hope that their efforts would one day yield an era in which the people knew true peace and the horrors of war were a hazy memory of the past.

Byleth - Guardian of Order
 * Byleth helped Dimitri to finally crush the ambitions of the Empire. After the war, Rhea stepped down from her role as archbishop, and Byleth swore to lead the Church of Seiros in her stead. He/She helped to guide the Holy Kingdom of Faerghus as it brought leadership to the newly unified Fódlan and worked tirelessly to create a peaceful world free from the shackles of oppression.

Etymology
Byleth is a variation of Beleth, a king of Hell. According to Pseudomonarchia Daemonum, Ham, Noah's son, was the first in invoking him after the flood, and wrote a book on mathematics with his help.

Trivia

 * Byleth's default name in Japanese differs slightly between genders, as a male Byleth is spelled "ベレト" (Bereto), while the female is "ベレス" (Beresu).
 * Byleth's artwork shows them wielding the Sword of the Creator.
 * Byleth is the first Avatar character since Mark to not feature a customizable appearance. Their male and female designs are fixed and cannot be edited by the player.
 * Byleth is the first character in Fire Emblem Heroes to be made available either through regular summoning, or via recognition of another game's data. At the launch of Three Houses, Heroes players that play both games on the same Nintendo Account will receive a free Byleth unit.
 * Byleth is the first avatar to fully appear in animated cutscenes without being obscured in some manner from a third person view or watching scenes unfold from a first person perspective. This is due to Byleth's lack of customizable physical features.
 * Byleth is the first and only Avatar character to be referred with neutral pronouns in the game. The only time they are specifically assigned a gendered pronoun is in their epilogue.
 * Although Byleth's age is listed as "???", likely so the player can imagine what age they are, they are most likely around 20 years old at the most at the start of game, as Jeralt had left the Knights 20 years prior.