General Durahan is an antagonist from the Monster Rancher anime who serves as one of the most powerful commanders in the evil Moo's army. His appearance is that of a suit of armor resembling a knight, and consistent with the mythical Dullahan from Irish folklore, he is often depicted without a head, carrying his helmet under his arm. This visual design also bears a resemblance to Moo’s own humanoid form, though Durahan is notably smaller in stature.

Durahan is introduced as the successor to the Big Bad Four, sent by Moo to destroy the main characters known as the Searchers after they defeated Moo’s previous top lieutenants. His personality is marked by immense pride in his own strength and a significant degree of ambition. While he is a loyal commander, he is secretly power-hungry and harbors a deep desire to overthrow his own master. When his attendant Lilim suggests betraying Moo and seizing the Magic Stone for himself, Durahan is delighted by the prospect, showing that his loyalty is ultimately secondary to his own ambition. He sees the Searchers not just as obstacles, but as worthy opponents, declaring that destroying them is necessary to avenge the fallen Big Bad Four while also plotting to usurp Moo’s power.

Throughout the second season of the anime, Durahan acts as a recurring threat, often sending powerful monsters from his collection to challenge the Searchers. His major plan culminates in successfully obtaining the Magic Stone, at which point he moves to betray Moo and use its power for himself. However, his betrayal fails when Lilim, choosing loyalty to Moo over Durahan, turns his own troops against him. During the ensuing battle aboard his airship, Durahan is defeated by the Searchers, with Mocchi’s Mocchi Cannon being a decisive blow that shatters Durahan’s sword. As his ship crashes, Durahan fatally stabs Lilim, dying himself in the wreckage.

Durahan makes a dramatic return in the third season, resurrected by his loyal minion Weed. However, the resurrection is incomplete, leaving Durahan as nothing more than a living head. To compensate for this and to continue his quest for power, he forcibly transforms Weed into a cybernetic body to serve him. As the main antagonist of the final season, his goal shifts to absorbing the soul of Moo, who was previously destroyed, in an attempt to gain ultimate power. In a climactic ritual, Durahan and his followers Poison, Weed, Mum Mew, and Gobi fuse with Moo’s Mystery Disc, creating a powerful armored warrior known as the Ruby Knight. The ritual backfires, as Moo's malevolent soul begins consuming Durahan and his team from within instead of obeying his control.

The character’s most significant development occurs in the series finale, where the Searchers enter Moo’s soul to fight the evil entity from the inside. Witnessing the destruction and consumption caused by Moo’s hatred, Durahan undergoes a redemption. He and his followers join their thoughts with the heroes, providing the necessary power for the legendary Phoenix to destroy Moo’s soul forever. After this final battle, Durahan is fully restored, regaining his complete body, and turns away from his evil past. He and his team then dedicate themselves to helping restore the world.

In terms of combat abilities, General Durahan is a formidable swordsman who attacks primarily with his blade. He can use it for standard slashing attacks, but his true power lies in his ability to fire powerful energy beams and projectiles from the sword, making him a threat at both close and long range. His minions include a recurring team of monsters: the plant-like Weed, the insectoid Poison, the feline Mum Mew, and the ogre-like Gobi. He also commands a vast collection of other monsters, which he often keeps frozen in ice until he is ready to unleash them on his enemies.