Fire Emblem Echoes: Shadows of Valentia (Nintendo Cinematic Universe)

Fire Emblem Echoes: Shadows of Valentia is a Japanese graphic novel.

Summary
Alm and Celica aim to bring an end to the war through opposite methods, with Alm fighting to resolve the war through battle, while Celica attempts to find a peaceful end through guidance from the Goddess Mila.

Plot Elements

 * The continent of Valentia was once divided between the Earth Mother Mila and the War Father Duma, sibling gods who split up and formed rival nations devoted to worshiping them: Mila's Kingdom of Zofia, and Duma's Empire of Rigel.
 * The two deities, who each held extreme viewpoints on the world, ended up corrupting their subjects, and Zofia was eventually swallowed in a war triggered by its military leader, Chancellor Desaix, who attempted a coup d'état.
 * Rigel's ruler Emperor Rudolf used this opportunity to lead Rigel's armies across Valentia in an attempt to conquer both countries.
 * A village boy named Alm sets out on a quest to overthrow Desaix and drive Rudolf out of Zofia. Meanwhile, his childhood friend Celica, the exiled Princess Antheise of Zofia, embarks on a pilgrimage to discover Mila's whereabouts after she vanishes, causing a drought in Zofia. The two childhood friends meet at Zofia Castle, but part ways when Alm is unwilling to attempt to find a peaceful resolution with Rudolf.
 * Alm invades Rigel and defeats Rudolf, who reveals with his dying breath that Alm is actually his son Albein Alm Rudolf. It is then explained that Rudolf's invasion was intended to strengthen the continent's military forces and create a champion capable of defeating Duma and Mila, who have both fallen into insanity due to their extreme power.
 * Alm infiltrates the Duma Temple and slays Duma with Celica's aid. With Duma's defeat, both deities disappear from the world.
 * Alm and Celica marry and unite Valentia under their rule.