Rhea

"All I ask is that you guide these open minds with virtue, care, and sincerity."

- Rhea's instruction to Byleth upon choosing a House.

Rhea is a character in Fire Emblem: Three Houses. She is the archbishop and supreme leader of the Church of Seiros. At Garreg Mach Monastery, Rhea can help Byleth increase their rank in Reason, Faith, Brawl, and Swords. She possesses a major Crest of Seiros.

Profile
Rhea is the Archbishop of the Church of Seiros and leader of the Knights of Seiros as a result. She serves as a key figure for the Officers Academy as well, assigning missions to the three houses each month.

Secretly, Rhea is one of the original children of the progenitor god Sothis, and also Seiros, the saint who founded the Church of Seiros, defeated Nemesis, and helped found the Adrestian Empire.

In the ancient past, Rhea and the other Children of the Goddess were born of Sothis's blood when the progenitor god arrived in Fódlan. She and the other children coexisted with the native Agarthans and shared their knowledge with them, leading their shared civilization to become technologically advanced and prosper. The Agarthans enacted various wars among themselves, eventually thinking of themselves as gods and turning on Sothis and the other Nabateans. Eventually, the Nabateans defeated them, returning peace to the land, and the remnants of the Agarthans fled into hiding underground, leading them to become Those Who Slither in the Dark.

In return, Those Who Slither in the Dark convinced Nemesis, a bandit, to invade the Holy Tomb, where Sothis was sleeping after exhausting herself healing the land from the destructive war, in order to steal Sothis's body. From Sothis's body, Those Who Slither in the Dark supplied Nemesis with her crest and the Sword of the Creator. Armed with the relic, Nemesis returned to Zanado to massacre the rest of the Nabateans to make Heroes Relics and crests from their bodies. Rhea was the only survivor of the massacre and left one of the few surviving Nabateans.

Desperate for revenge, Rhea, now calling herself Seiros, wandered the lands looking for allies to oppose Nemesis and his forces. She allied with her fellow survivors (whose human forms came to be known as the Four Saints) and Wilhelm I, to whom she granted her crest, to oppose Nemesis in the War of Heroes, eventually killing Nemesis in battle at the Tailtean Plains and leading to the creation of the Adrestian Empire and the extended influence of the Church of Seiros with her as its head. The church rewrote history, hiding the existence of the Children of the Goddess, Agarthans, and the true origin of crests and relics, and revising the origins and allegiances of Nemesis and his crest-wielding allies, the Ten Elites.

Still awash with grief at the death of Sothis, Rhea secretly devoted herself to experimenting on implanting her mother's crest stone into created bodies in an attempt to revive her mother. Her twelfth failure, a young woman, fell in love with the then captain of the Knights of Seiros, Jeralt, eventually becoming pregnant. However, the birth resulted in a child who was not breathing and left the mother dying. Acquiescing to the mother's dying wish, Rhea implanted the crest stone she had implanted into the mother into the newborn, saving the child, Byleth. Jeralt, having grown suspicious of Rhea as a result of his wife's death and his child not having a heartbeat, later chose to flee Rhea's employ.

Years later, when Jeralt and Byleth are reintroduced to Rhea after saving Edelgard, Dimitri, and Claude, Rhea asks for Byleth to become a new professor at Garreg Mach Monastery, concealing her hope that Byleth would be a host body for a revived Sothis. After Byleth's soul fuses with that of Sothis, Rhea brings Byleth to the Holy Tomb, hoping to complete the transformation. However, her plans are shattered when Sothis does not revive and the tomb is invaded by Edelgard.

After Edelgard's declaration of war on the Church of Seiros, Rhea personally leads the defense of Garreg Mach Monastery against the Adrestian Empire. When the defense falters as a result of either Duke Arundel's reserve troops or Byleth's intervention, Rhea transforms into her true form, the Immaculate One, as a last resort but fails to prevent its capture.

On routes other than Crimson Flower, Rhea goes missing after her failure to defend Garreg Mach Monastery. It is later revealed that she was captured by the Adrestian Empire after the battle at Garreg Mach and imprisoned in the Empire's capital, Enbarr, forcing the Knights of Seiros to join forces with Byleth in order to confront Edelgard and free her.

On the Silver Snow and Verdant Wind routes, Rhea accompanies Byleth as Byleth confronts and defeats Thales, the leader of Those Who Slither in the Dark. However, Rhea is gravely injured attempting to shield Byleth's forces from Agarthan missiles in her dragon form. In the Silver Snow route, Rhea becomes berserk after revealing the truth and apologizing to Byleth, forcing Byleth to fight and defeat her in her dragon form. If Byleth has an S-rank support with Rhea, she survives and reforms the Church of Seiros in the epilogue. In the Verdant Wind route, Rhea reveals she only has a short time to live due to her injuries sustained and reveals the truth of the goddess, Agarthans, Nemesis, the Ten Elites, and the origins of crests and Heroes Relics.

In the Crimson Flower route, after failing to defend Garreg Mach, Rhea then flees to the Holy Kingdom of Faerghus and builds her forces there in alliance with Dimitri. After Dimitri is killed and their combined forces defeated at the Tailtean Plains, she seizes control of Fhirdiad, and as the Black Eagle Strike Force prepare to storm it, she orders Catherine and Cyril to torch the city. Nevertheless, Byleth and Edelgard enter the city and kill her.

Personality
Rhea is what one would expect of a head of a church: benevolent, kind, and compassionate. While she is such to the devout followers of the church and the students and faculty of the Officers Academy, she is ruthless and dismissive of those who oppose the church with violence (though she will accept and even employ nonbelievers if they are peaceful toward her). Any who oppose the church with violence are dealt with by her righteous vision of justice and she even labels their defeats and misfortunes as judgement of the Goddess.

Deeply tormented by her Sothis's death, Rhea is obsessed with the idea of resurrecting her, in part as a way to heal from her own suffering and return to the life she once knew. In the Crimson Flower route, where Byleth, the bearer of Sothis's crest stone and consciousness, chooses to protect Edelgard instead of killing her, Rhea becomes increasingly unhinged by this perceived betrayal, eventually reverting to her vengeful Seiros persona and becoming obsessed with killing Byleth, believing them to be keeping her mother from her.

However, in the Silver Snow and Verdant Wind routes where Byleth does not support Edelgard, Rhea maintains her sanity and becomes horrified and regretful of her actions, admitting that she was driven by selfish and immature motives, and that it was wrong to view Byleth as nothing more than a new host body for her mother, handing over her authority as she believes she is no longer worthy of the degree of influence she had.

Base Stats
Battle of Garreg Mach

Growth Rates

 * 45%
 * 35%
 * 45%
 * 40%
 * 40%
 * 40%
 * 30%
 * 40%
 * 70%
 * }

Maximum Stats

 * 86
 * 52
 * 65
 * 56
 * 56
 * 56
 * 43
 * 60
 * 97
 * }

Learnt Magic

 * D
 * Fire
 * Heal
 * D+
 * Bolganone
 * Nosferatu
 * C
 * Recover
 * C+
 * B
 * B+
 * A
 * Ragnarok Agnea's Arrow
 * A+
 * }
 * B
 * B+
 * A
 * Ragnarok Agnea's Arrow
 * A+
 * }
 * A
 * Ragnarok Agnea's Arrow
 * A+
 * }
 * Ragnarok Agnea's Arrow
 * A+
 * }
 * A+
 * }
 * }
 * }

Supports
Rhea can form a support with Byleth only. She can form an S-Support with both genders of Byleth.

Possible Endings
Rhea and Byleth
 * After finally saving both Fódlan and Rhea from Crisis, Byleth ascended the throne as the first leader of the United Kingdom of Fódlan. From his temporary residence at Garreg Mach Monastery, he endeavored to restore and develop Fódlan. Having narrowly escaped death, Rhea took time to recover her strength before returning to her role as archbishop. Upon her return, she applied herself to rehabilitating the church and helping those who had suffered because of the war. Thereafter, the two worked closely to forge new policies and achieve progress for Fódlan. The pair’s collective work came to be thought of as nothing short of miraculous.

Etymology
Rhea is a Greek titan known as the "Mother of the Gods." The name may also refer to the mother of Romulus and Remus, the mythical founders of Rome.

Trivia

 * Rhea shares her Japanese voice actor, Kikuko Inoue, with Deirdre in Heroes.
 * Rhea shares her English voice actor, Cherami Leigh, with Mae and Emma in Echoes: Shadows of Valentia as well as Caeda, Gwendolyn, and Cecilia in Heroes.
 * Rhea is one of the characters who can have S-Supports with both a male and a female Byleth. The others are: Mercedes, Dorothea, Edelgard, Sothis, Linhardt, Alois (platonic) and Gilbert (platonic as well)