Prince Arren, heir to Enlad's throne, commits patricide at the story's beginning, stabbing his father the king under the influence of an unexplained impulse called "Uneinheit". This act forces him to flee the kingdom carrying his father's magic-infused sword, which he initially cannot draw.

Arren possesses a handsome appearance marked by dark brown hair and deep-set eyes, often reflecting innocence or deep anguish. He typically wears an old blue shirt, sometimes layered with a purple gold-edged robe or a brown cape. Though skilled with a sword, his vulnerability emerges during moments like being captured by slavers while asleep.

His psyche manifests fragmentation as a shadowy doppelgänger representing his inner light, which relentlessly follows him. This duality stems from existential terror regarding mortality, exploited by the sorcerer Cob who gains control by learning Arren's true name, "Lebannen" (meaning Sorbus commixta in the ancient tongue). Guilt over the regicide surfaces when he confesses the act to Therru, despite considering his father a "great man".

Key relationships define his journey: Sparrowhawk (Ged) serves as a mentor and paternal figure after the king's death. Arren's initial antagonism toward Therru, sparked by her disdain for his disregard for life, transforms through shared vulnerability—particularly after his kidnapping by Cob's forces—into mutual romantic feelings. Therru's revelation of her true name "Tehanu" mirrors her use of "Lebannen" to shatter Cob's psychological hold, restoring Arren's agency.

Passivity characterizes much of Arren's narrative as he follows Sparrowhawk, suffers repeated captures, and sinks into depressive detachment. His pivotal moment arrives confronting Cob: unsheathing the enchanted sword severs Cob's hand, nullifying the sorcerer's magic and triggering his physical decay. Following this conflict, Arren acknowledges responsibility for his patricide and departs to face judicial consequences in Enlad, promising Therru he will return after atonement.