Agan Mardrus, son of the Sand Tribe chief and heir to its leadership, hails from the desert people. His early life included a close friendship with Morte, though the anime adaptation omits this connection, depicting him instead as a smuggler who encounters the World Destruction Committee by chance. He is physically distinguished by flaming red hair, typically hidden beneath a green naval cap, and facial markings of crossed arrows. His attire features a long green overcoat, an orange turtleneck shirt, and blue pants secured with a belt.

Generally laid-back, Agan possesses a short temper easily ignited by adversaries. He stands as one of the most mature members within his group, exhibiting the disposition of an 18-year-old marked by heightened impulsiveness during conflict. His combat prowess centers on unique Earth-based Blood Skills, making him the sole party member wielding such abilities. These include conjuring sandstorms, blinding toxic mists, and projecting razor-sharp stalactites known as Desert Horn. His Life Skills provide defensive and supportive capabilities, notably the Wall of Stone for blocking damage and a unique party-wide speed enhancement.

Previously second-in-command of the Golden Lions, a human resistance faction opposing the ferals, Agan departed after a member's betrayal. This event followed his earlier disillusionment when a childhood feral friend treated him cruelly during adulthood. His inherent leadership potential is demonstrated by his ability to command respect from tribal members, exemplified in a specialized attack summoning ten Mole Tribe allies to assault enemies.

Across different adaptations, his narrative integration varies. While the anime presents him as an independent smuggler without prior ties to Morte, other media emphasize their shared history and his eventual, albeit reluctant, alignment with her cause. A recurring character trait involves him apologizing excessively, even during confrontations with adversaries.