Hilmes, also known as Lord Silvermask, is a central figure in The Heroic Legend of Arslan: Dust Storm Dance. He is the son of Osroes, the former king of Pars, making him a cousin to the series' protagonist, Prince Arslan, and the rightful heir to the Parsian throne. His defining physical characteristic is a silver mask he wears to conceal the right side of his face, which was horribly burned in a fire that he barely survived as a child. This traumatic event was no accident; it was an assassination attempt orchestrated by his own uncle, Andragoras, the man who usurped the throne and is now the current king of Pars. Driven from his homeland and left for dead, Hilmes was forced into exile, eventually becoming a key commander in the army of the rival nation of Lusitania. He uses this foreign power as a tool to invade Pars, seeking to reclaim the kingship he believes is his by divine right.

In terms of personality, Hilmes is defined by his towering ambition and an unyielding desire for vengeance against Andragoras. He firmly believes the throne of Pars is his birthright and never questions his own abilities or his claim. This conviction fuels a deep-seated rage, particularly at skilled warriors like Daryun and Narsus, who choose to follow what he considers a lowly usurper's son in Arslan. He is prone to cruelty and is willing to sacrifice anyone, including innocent people, to achieve his goals, often solving problems with his sword due to a lifetime of having to fight for his survival. He is extremely short-tempered, though he possesses the discipline to suppress his anger when the situation demands strategic patience. A significant psychological scar from his childhood trauma is a powerful pyrophobia, an intense and debilitating fear of fire.

The Dust Storm Dance anime significantly deepens Hilmes's character, moving him beyond the role of a straightforward antagonist. The story humanizes him by exploring his past and revealing his deep, genuine care for Princess Irina of Maryam, a blind princess who was his sole companion during a period of his exile. Their bond is his one redeeming human connection. Hilmes refuses to reveal his identity to Irina upon their reunion, feeling he is not worthy of her until he has reclaimed his throne and his true status. This relationship becomes the primary test of his motivations; when Irina's life is threatened by his Lusitanian allies, he does not hesitate to turn against them to ensure her safety, prioritizing her life over his long-cherished political alliances. This act demonstrates that his rage, while immense, is not the only thing that drives him, opening a path toward possible redemption.

Throughout the story, Hilmes's primary role is as a foil to Arslan. Where Arslan is progressive, merciful, and seeks to build a kingdom based on the service of his people, Hilmes represents the old, feudal model of kingship—someone who believes his subjects are tools to serve his will by divine right. His key relationships are largely defined by his quest for the throne. He commands fierce loyalty from followers like the general Sam and the young warrior Xandes, who are drawn to his cause. Conversely, he is locked in a bitter rivalry with Andragoras, whom he hates for his treachery, and with Arslan's key protectors, Daryun and Narsus, whom he respects but resents for their allegiance.

Notably, Hilmes is an exceptionally skilled swordsman, considered to be in the highest tier of warriors in the series. His combat prowess allows him to match or even potentially exceed legendary fighters like Daryun, whom he considers a rival. He has demonstrated the ability to defeat renowned masters such as the veteran warrior Vahriz. Beyond his individual fighting ability, Hilmes possesses a forceful charisma that enables him to attract and command unwavering loyalty from powerful men, a crucial asset that has convinced figures like the distinguished general Kharlan to commit treason in order to place him on the throne.