Oscar is one of the playable characters in Fire Emblem: Path of Radiance, and its sequel Fire Emblem: Radiant Dawn. He is one of the first characters that will join your team, and helps train Ike to become leader of the Greil Mercenaries. He starts out as a Lance Knight. He is a former member of the Crimean Royal Knights, and a current member of Greil's Mercenaries along with his younger brothers Boyd and Rolf. Later in the game if the player chooses to let Oscar and Boyd wield Bows in their class upgrades, they can perform a powerful Triangle Attack by having two of the brothers moving one unit away from the enemy and have the last brother attack with his bow.
In Radiant Dawn, he returns as a Lance Paladin and first appears when rescuing Lucia from the rebel army at Fort Alpea. He then joins Ike and the other Greil Mercenaries into Begnion to fight with the Laguz Alliance against the Begnion Empire. During their travels, he indulges in his passion for cooking, and takes the role of chef for the Laguz army.
After the conflict ends, Oscar leaves the Greil Mercenaries and rejoins the Crimean Royal Knights. Despite his role as a knight, he continues to work with the mercenaries on his spare time.