Duelle is an anthropomorphic onion warrior within Fa'Diel, frequently appearing across various locations to offer travelers guidance and combat advice. He carries a miniature spear and exhibits a straightforward, no-nonsense personality, openly expressing disdain for individuals like the merchant Niccolo, whom he views as deceitful.

In Domina, Duelle intervenes in conflicts, such as pacifying a confrontation between Elazul and Shiloh at the local tavern. He swiftly disarms Elazul despite the latter underestimating him due to his size. Duelle later apologizes to Rachel for Elazul's behavior, identifies the Jade Egg in her possession as an Artifact, and guides Elazul and Shiloh to the monster-infested Mekiv Caverns before departing.

He assists the protagonist in multiple scenarios, providing foundational combat tutorials explaining basic mechanics on Luon Highway or within Mekiv Caverns. During Niccolo's Business Unusual, he openly criticizes Niccolo's merchandise as worthless junk to prevent Teapo from making a costly purchase. Spotting a Monster Egg in western Domina, Duelle instructs the protagonist on capturing and raising them.

Duelle displays protective instincts toward companions like Teapo. During Teatime of Danger, he searches for her after she wanders into Mindas Ruins to collect tea leaves, eventually reuniting with her. In Seeing Double, an impostor mimicking Duelle deceives Teapo into surrendering her pumpkins. The real Duelle exposes the deception, prompting Teapo to express relief at his integrity.

His personality combines a diminutive, unassuming appearance with a bold and principled demeanor. He actively opposes dishonesty and prioritizes direct action, traversing lands to support others through practical aid or candid advice. This consistency is evident across his appearances, dedicated to upholding straightforward values and aiding those in need.