Duclis is a character from the anime Slayers Revolution, where he serves as a tragic antagonist. His current form is that of a large, muscular beastman with the features of a gray tiger. In this body, he stands notably taller than the swordsman Gourry Gabriev. He wears a thin black headband with straps hanging down one side of his face and a black cape over a set of incomplete Zanaffar armor.

Before his transformation, Duclis was a human and a close friend of the royal family of the kingdom of Taforashia. When a deadly magical illness known as the Durum sickness struck the kingdom, Duclis and the kingdom's prince, Pokota, worked together to try and heal the afflicted. However, the disease spread too quickly for them to stop. The powerful priest Rezo intervened to save the population by placing all the residents of Taforashia into a magical sleep until a cure could be found. To allow Duclis and Pokota to continue their search for a cure without succumbing to the disease themselves, Rezo transferred their spirits into the new, resilient animal-like bodies they inhabit in the series.

Motivated by a desperate desire to save his frozen kingdom, Duclis becomes a conflicted figure. He believes that no other nations are taking action to help Taforashia, and out of this despair, he makes a morally questionable decision. He allies himself with the marquess Gioconda of the neighboring country of Ruvinagald, who seeks to take control of the sleeping Taforashia. Duclis hopes that by cooperating with Ruvinagald, he can gain the resources needed to break the curse on his people. In this alliance, he acts as an enforcer and confronts the series' protagonist, Lina Inverse, and her companions when they investigate the king's mansion in Taforashia.

Duclis's relationship with Prince Pokota is central to his character. The two share a deep history as friends and comrades, both having been transformed by Rezo for the same noble purpose. However, their paths diverge when Duclis chooses to work with Gioconda, placing them in opposition. Duclis’s disillusionment with the outside world comes to a breaking point when he discovers that Gioconda has been stealing the aid money sent by other countries to help Taforashia. Feeling betrayed yet further by the world's inaction, he turns on her.

His retribution is swift and terrible. He activates the magical Zanaffar armor that Gioconda wears, which awakens into a perfect form and consumes her. After this, Duclis makes a pact with the sentient Zanaffar itself, agreeing to destroy every country that refused to help Taforashia in exchange for creating more suits of the perfect armor. This decision leads to his own tragic downfall. As Lina and her friends defeat the awakened Zanaffar, the flawed Zanaffar armor that Duclis himself wears begins to consume his body from within. His form grotesquely mutates, forcing him to walk on four legs like a centaur. In his final moments of self-awareness, he confronts Prince Pokota and offers him the chance to end his suffering, an offer the prince refuses. Duclis then departs, leaving his ultimate fate ambiguous.

In terms of abilities, Duclis is a formidable physical fighter, relying on his immense strength and the power of his Zanaffar armor. The armor grants him a high degree of magical defense, making him nearly impervious to direct spells. He wields a massive battleaxe in combat and is also capable of firing a laser-like breath weapon and casting low-level magic. His character arc is one of a loyal guardian whose desperation turns to nihilism, leading him to betray his own principles and ultimately be destroyed by the very power he sought to control.