|First game||Fire Emblem: Thracia 776|
|Voiced by (English)||Erin Fitzgerald|
|Voiced by (Japanese)||Mikato Takahashi|
Olwen is a playable character from Fire Emblem: Thracia 776. She is the eighteen-year-old younger sister of Reinhardt, whom she initially admires. She leads a reconnaissance squad in the Friege army.
Olwen makes her first appearance in Chapter 10 of Thracia 776 when she and her subordinate, Fred, are working on surveillance duty at Noel Canyon. In their scene with Largo, it is revealed that Olwen has a strong dislike for Kempf, who despises her out of envy towards Reinhardt. When Noel Canyon is attacked by Leif's army, Olwen and Fred fight against them for a short while, but eventually decide to leave in order to ask Kempf for reinforcements.
At the start of Chapter 11, Olwen requests reinforcements from Kempf, who points out her failure to identify the enemy army that attacked Noel Canyon. Once Kempf openly shows his disregard for Largo's life, she speaks out against him in shock. After he taunts her and claims that Reinhardt's greatest skill is seducing women, Olwen attacks Kempf out of anger, causing him to label her as a traitor. Following her imprisonment in Dandrum Fortress, Kempf reveals that he intentionally provoked her in hopes of removing Reinhardt from his position. He also uses Olwen as a hostage to force Fred to fight against Leif's army to the death.
In her cell, Olwen finds several children. Upon learning that they were captured in the child hunts, she becomes horrified by the actions of her country. She is later rescued by Fred, and reveals that she now doubts their cause. Fred advises her to join Leif's army alongside him, which she agrees to after hearing that Leif's ideals are similar to her own.
In Chapter 16A, Olwen asks Leif to allow her to approach Kempf in order to provoke him. If she speaks to Kempf during the chapter, she points out his cowardice and inability to compare to her brother. Her words deeply anger Kempf, causing him to abandon his strategic position of defense that he had been ordered to remain at.
During the battle against Reinhardt in Chapter 22, Olwen can speak to him. In their conversation, she reveals that she has chosen her own path of standing against the Grannvale Empire, with her reason being her opposition to the child hunts. She also receives the Blessed Sword from Reinhardt as a parting gift.
After the war, Olwen returns to Friege and contributes in its reconstruction. It is mentioned that whenever she remembers Reinhardt, she becomes infuriated by how pitiful he was. She also marries Fred, who is surprisingly ordinary, much unlike her brother.