Sometime before the events of the game, Orson was well-known among the knights for his love and devotion to his wife, Monica. After her death, his behavior greatly changed and he made a deal to betray Renais and side with the Grado Empire in exchange for Monica's resurrection.
He is first seen accompanying Ephraim, Kyle, and Forde during their assault on Renvall Castle. Unbeknownst to his allies, Orson has secretly betrayed them, as shown at the end of Chapter 5x where Tirado refers to him as a "friend on the inside."
After attempting to escape from Renvall Castle, he, Ephraim, Kyle, and Forde are captured.
When Eirika's party reaches Renvall, they are greeted by Orson, who is attempting to obtain Eirika's bracelet. However, Seth is suspicious and points out a few things that blow Orson's cover:
- "Why did no enemy reinforcements come from inside the castle?"
- "Why free yourself and leave Prince Ephraim in chains?"
- "Why do you have a sword concealed in your doublet?"
Orson reveals that he turned to Grado for a chance to bring back Monica. Tirado arrives and dismisses Orson, who returns to Renais to be with his wife.
In Chapter 16, is is revealed that Orson has been proclaimed as king due to the absence of the royal siblings. Orson becomes increasingly deranged, leaving Renais to rot, refusing meals, and staying in his chambers, refusing to let anyone in. He enters with a gift for his wife (believing that she is still alive, when she simply just says "Darling") after which he is interrupted by Lyon and Riev, which upsets him. When Lyon states that Ephraim and Eirika are on their way back to the castle, Orson apologizes to Monica and heads out to confront the siblings. In the end, he is killed and his wife's body is destroyed.
Before his descent into madness, Orson was widely seen as a quiet but kind man. He was well known for his devotion to his wife, Monica, which was ultimately his undoing. Her death had a massive impact on him, leaving him severely depressed, and so he leapt at the opportunity offered to him by Lyon to revive her, even if it meant betraying Renais. His desperation to have Monica back has led him to obsess over his love for her and completely ignore that she was a rotting corpse and barely coherent.
Fire Emblem Gaiden & Echoes: Shadows of Valentia
The Black Fang
Fire Emblem: The Sacred Stones
Fire Emblem Awakening
Fire Emblem Fates
Fire Emblem Warriors
Tokyo Mirage Sessions ♯FE
Fire Emblem Heroes
Fire Emblem: Three Houses