Osmond is the elderly, white-haired headmaster of Tristain Academy of Magic and a respected authority within the academy and the Tristain kingdom. A Square-level mage with wind affinity, his familiar is a mouse named Motsognir, which he frequently uses to spy on female students, particularly their undergarments.

Thirty years before the main events, Osmond encountered an American soldier from the Vietnam War era during a dragon attack. The soldier saved Osmond's life using an item later named the Staff of Destruction before succumbing to prior injuries. Osmond recovered two staffs; he buried one with the soldier and presented the other to the Tristain Royal Court, establishing his link to objects from other worlds.

During the Familiar Spirit Summoning Exam, Osmond witnessed Louise de la Vallière summon Saito Hiraga. Examining Saito's Gandálfr runes, Osmond deduced a connection to the Void element and instructed Professor Colbert to maintain confidentiality. He later managed security for the Staff of Destruction stored at the academy, warning staff about the thief Fouquet the Crumbling Dirt.

When Fouquet stole the staff during a royal visit, Osmond delegated the recovery task to Louise, Kirche, Tabitha, and his secretary Longueville instead of involving the royal court. After the staff's retrieval, he explained its origins to Saito, recounting the soldier incident and confirming the existence of the second staff.

Osmond balances his official duties with habitual comedic actions centered on voyeurism. Despite occasional lapses in dignity, he retains the respect of the academy community and the trust of the Tristain royal family.