- For fighter info, see Byleth (Super Smash Bros. Ultimate).
Byleth Eisner is the default name for the main protagonist of the Nintendo Switch game Fire Emblem: Three Houses.
Byleth Eisner is the player's surrogate character in Fire Emblem: Three Houses, succeeding Robin from Fire Emblem Awakening and Corrin from Fire Emblem Fates. Unlike them, however, their only customizable features are the name, gender, and birthday. They are a silent protagonist, with the majority of their vocal lines only being heard in battles.
Part I: White Clouds
One day, Byleth and their father, Jeralt Eisner, have a chance encounter with three young nobles who come under attack from bandits. These nobles are Princess Edelgard von Hresvelg of the Adrestian Empire, Prince Dimitri Alexandre Blaiddyd of the Holy Kingdom of Faerghus, and Lord Claude von Riegan of the Leicester Alliance. During the battle, Byleth sacrifices themselves to protect Edelgard, which triggers the awakening of a mysterious amnesiac being named Sothis who ultimately protects Byleth, grants them special powers, and stays in their subconscious. After the battle, Jeralt, Byleth, and the nobles are brought to Garreg Mach Monastery, where Jeralt is reluctantly reinstated as captain of the Knights of Seiros and Byleth is offered a teaching position in the Officers Academy by Rhea, the archbishop of The Church of Seiros - Fódlan's dominating religion. It is here where the player can choose which house they want to teach for the next year: The Black Eagles (led by Edelgard), The Blue Lions (led by Dimitri), and The Golden Deer (led by Claude). Byleth instructs the students on attacks and battle strategies, often going into the battlefield with them on behalf of the Knights.
As the teaching year progresses, Byleth and the students begin to uncover frightening details on the nature of the Church's Crests and the ancient weapons known as the Hero's Relics. Various transgressors also appear to plot against the Church, including masked warriors known as the Flame Emperor and the Death Knight, the Church's western branch, and a sinister cult who calls themselves "those who slither in the dark". One of them tries to steal one of the relics, the Sword of the Creator, but Byleth arrives in time to stop them. However, to their surprise, the sword activates in their hands. Rhea sees this and allows them to keep it.
Unfortunately, one of the cult's assassins, Kronya, murders Jeralt. Byleth and Sothis later find Jeralt's diary and ultimately find out about the truth of their pasts; Byleth was born in the Imperial Year 1159 in critical condition and not breathing. To save them, Rhea used the Crest Stone of Flames (better known as the titular "Fire Emblem") from their mother and Church nun, Sitri, while also attempting to implant the goddess Sothis within them so she can be reborn; this resulted in not only Byleth recovering, but also Sitri dying. Unfortunately, this also had the consequence of Byleth being near emotionless throughout their entire childhood as Sothis lay dormant. Jeralt notices this odd behavior and uses a fire as a means of faking their deaths and fleeing Garreg Mach Monastery, fearing what Rhea has planned for his child. The two would spend the next twenty years wandering Fódlan as mercenaries.
Upon discovering this, Byleth goes in pursuit of Jeralt's killers all the way to the Sealed Forest. Unfortunately, they are lured into a trap and banished into a realm of darkness. As a means of escape, Sothis willingly gives up her individuality to merge with Byleth and grant them access to the full extent of her powers, which allows them to defeat the cult. Afterwards, Rhea leads them to the Holy Tomb located deep below Garreg Mach in an attempt to reawaken Sothis. However, the Flame Emperor interrupts the ritual when they raid the Tomb with allies from the Adrestrian Empire. During the ensuing battle, the identity of the Flame Emperor is revealed to be Edelgard herself; she accuses the Church of corruption for their propagation of worshiping the Crests, something that led to the deaths of her siblings, and declares war on the Church (normally, Byleth will side with the Church and the other two houses. However, if they chose to teach The Black Eagles house, they can optionally choose to defect to their side). At the end of battle that follows soon after, Rhea reveals herself to be a dragon, Byleth is knocked into a coma after getting involved in an accident, and the Adrestrian Empire emerges victorious.
Five years later, Byleth reawakens from the coma to find Fódlan thrown into chaos as the Adrestrian Empire, the Kingdom of Faerghus, the Leicester Alliance, and the Church of Seiros have been in constant war with each other. It is here where the paths begin to diverge based on which house Byleth chose to teach.
If Byleth chose The Black Eagles house, they will team up with Edelgard and help eliminate the other two armies by killing Claude (exiling is also an option for him) and Dimitri. The Empire army advance their forces onto the Kingdom's capital in pursuit of Rhea, during which Edelgard discovers her uncle to be an ally with "those who slither in the dark"; she chooses to keep his treachery a secret after they foil his attempt to destroy a fort as a way to exact his revenge on her for interrupting the cult's plans. In a moment of madness and desperation, Rhea transforms again into a dragon to set fire to the city, forcing Byleth and Edelgard to kill her. In the end, Edelgard unites all of Fódlan under the rule of the Empire, banishes the Church, and dedicates the rest of her life with Byleth to ending the cult.
If Byleth chose The Blue Lions house, they will team up with a now bitter, disillusioned, unstable, and exiled Dimitri, who is driven to exact revenge on Edelgard by any means necessary. Dimitri, now using Garreg Mach as his base, stages an all-out war between his new forces, the Empire, and the Alliance, with massive casualties on all sides. One of his trusted vassals sacrifices himself to fend off an assassin; Dimitri witnesses this and, after counsel from Byleth, abandons his thirst for vengeance. He then decides to rescue Claude and end the battle, resulting in Claude dissolving the Alliance, ceding his land to Dimitri, and departing Fódlan. He then goes to face Edelgard, wanting peace and to create an alliance with her. However, she angrily refuses and is eventually defeated and killed by him after an ensuing battle. In the end, Dimitri unites all of Fódlan under the rule of the Kingdom and Byleth becomes the new archbishop after Rhea steps down.
If Byleth chose The Golden Deer house, they will team up with Claude to invade the Empire. Upon arriving, they also find Dimitri and his Kingdom forces marching in, resulting in a massive three-way battle, during which Edelgard retreats and Dimitri is killed. Byleth and Claude make their way to a fort owned by the Empire and receive aid from the foreign nation of Alymra; Claude admits that he opened relations with them in secret and plans to open Fódlan's borders and end the country's isolationism. After they reach the fort and kill Edelgard, they find out that "those who slither in the dark" are the true manipulators of not only this war, but another one from 1000 years past. Eventually, the two defeat the members of the cult as well as the undead King Nemesis, the one who created the Crests after stealing power from Sothis and slaying her dragon kin. In the end, Byleth and Claude unite all of Fódlan and begin to open its borders and start relations with foreign lands.
If Byleth decides to side solely with the Church of Seiros, they will discover that Rhea has gone missing and will team up with her second-in-command Seteth and former Black Eagles students to form a resistance army dedicated to defeating the Empire. The resistance proceed to launch an invasion on the Empire, where they conquer its forts, kill Dimitri and Edelgard, drive Claude into hiding, and rescue Rhea. In the aftermath, one of Edelgard's vassals tells Byleth that "those who slither in the dark" are the true manipulators of all the tragedy and destruction that has happened to Fódlan. Upon hearing this, the resistance invades the cult's fortress and kills their leader. Rhea then reveals that she is one of the children of the goddesses and Byleth is a result of her countless attempts to reawaken her mother Sothis. She then suddenly has a degeneration-induced mental breakdown, turning into a colossal dragon, and goes on a rampage, forcing the resistance to kill her. In the end, Byleth unites the continent and becomes the leader of the newly formed United Kingdom of Fódlan.
DLC Side Story: Cindered Shadows
While Garreg Mach was built, the Four Apostles attempted to resurrect Sothis through the Rite of Rising, but ultimately failed and later disappeared. A thousand years later, Byleth and the students stop an intruder and in the process discover a secret underground settlement named Abyss, who are defended by the school's secret fourth house: the Ashen Wolves. They explain that they have an uneasy alliance with the Church of Seiros to ensure that the two groups do not meddle in each other's affairs, however lately mercenaries have been attempting to raid their settlement. Byleth and the students agree to help defend the Abyss but their liaison to the Church, Aelfric, privately warns them that some of the factions within the Church want the settlement purged, and believes that the mercenaries are after the Chalice of Beginnings, the key to completing the Rite of Rising.
Eventually, members of the Abyss find the Chalice but Aelfric is kidnapped and held for ransom by the mercenaries in exchange for it. Rhea willingly trades the Chalice for Aelfric as she believes that no one knows how to do the Rite. It is eventually revealed that the Ashen Wolves are the direct descendants of the Four Apostles and that Aelfric is the orchestrator of the raids. He then kidnaps the Ashen Wolves and takes the Chalice for himself. Rhea warns Byleth that Alefgard plans to use the Chalice by sacrificing the Ashen Wolves in an attempt to revive their mother, Sitri. Byleth arrives and rescues the Ashen Wolves but Alefgard proceeds with the ritual anyway; he consequently mutates into a beast, forcing the group to slay him. In the end, Rhea disbands the Ashen Wolves and allows them to return above ground. They all go their separate ways but promise to help each other and Byleth when the need arises.
Byleth was announced to be included in Ultimate at their gameplay presentation hosted by Masahiro Sakurai on January 16, 2020, confirming them to be the fifth and final fighter in Fighters Pass Volume 1.
Byleth not only wields their signature weapon, the Sword of the Creator, but also the three houses' signature regalia (Edelgard's axe named Aymr, Dimitri's spear named Areadbhar, and Claude's bow and arrow named Failnaught) as a reference to the game's branching storylines.
- Byleth is the most recent fighter in Smash history, as Three Houses was released on July 26, 2019.
- Byleth is the first character:
- To debut on the Nintendo Switch, with Min Min and Pyra and Mythra following suit
- To be revealed in the 2020s decade
- To come from a game released after Ultimate
- In designing Byleth, Masahiro Sakurai played an early version of Three Houses to get a feel for the character, as well as to ensure that Byleth's release was not to be delayed. This is a similar reason to him playing an early version of The Legend of Zelda: Breath of the Wild when design the new version of Link.
- Byleth, along with Robin and Corrin, are the only Fire Emblem fighters:
- To be avatars
- To be both genders
- To have projectiles
- Byleth and Robin are the only Fire Emblem characters to lack a Counter down-special.
- Both genders of Byleth have two different names in the Japanese version. They share this trait with Pokémon Trainer, Villager, Wii Fit Trainer, the Mii Fighters, and Inkling.
- It's also due to this name difference that they received two splash arts in their reveal trailer, being the first fighter to have this distinction, with Steve & Alex and Pyra & Mythra following suit.