King Hamdo is the primary antagonist of the story, serving as the self-proclaimed ruler of Hellywood, a massive, mobile fortress that operates as a war machine and a city-state. His background is largely shrouded in mystery, with the series offering no concrete details about his past, how he came to power, or how he acquired the fortress. There are hints that he may have been born into a position of authority or received some formal education, as he possesses theoretical knowledge of advanced military operations and strategies. However, his current mental state is so degraded that any past competence seems irrelevant to his present actions.

Personality is the most defining aspect of Hamdo. He is a deeply unstable, sadistic, and cowardly tyrant. His behavior is characterized by wild, unpredictable mood swings that shift from childish glee to explosive, violent rage in an instant. He is a narcissist who cannot tolerate frustration or defiance, and his temper tantrums are a central feature of his rule. Despite his immense power, he is fundamentally a coward, panicking at any direct threat to his own safety and showing no concern for the lives of his own soldiers, including the children he has forced into service. One of his earliest and most defining acts is shown to be strangling his own cat, establishing his casual cruelty and unstable nature from the outset. His madness is often portrayed as so extreme and childlike that it creates a disturbing contrast with the horrific reality of his actions.

Hamdo's primary motivation is the acquisition and control of water, the scarcest and most vital resource in this desolate world. His goal is to use the power of a young girl named Lala-Ru, who possesses a pendant capable of creating limitless water, to fully restore Hellywood's functionality and solidify his dominion. He is driven by the desire to crush the resistance force of Zari-Bars and to quell any opposition to his reign. Ultimately, his motivations are selfish and short-sighted, focused on satisfying his immediate whims and maintaining his position of power through fear and terror.

In the story, Hamdo acts as the oppressive force that creates the hellish environment the protagonist, Shu, is thrust into. He rules Hellywood through a regime of absolute terror, kidnapping children from villages to be trained as child soldiers and abducting women to be used as breeding slaves to produce more soldiers. He is the direct cause of immense suffering, including the brutalization of characters like Sara. His role is not that of a master strategist or a great conqueror, but rather a chaotic and destructive force of nature that corrupts everyone within his sphere of influence.

His key relationships are defined by fear and manipulation. His most important subordinate is Abelia, his second-in-command who is fiercely loyal and manages the day-to-day operations of Hellywood while Hamdo indulges his whims. Hamdo frequently abuses her, striking her in fits of rage only to immediately apologize and plead for her loyalty, revealing a deeply dysfunctional and codependent dynamic. His relationship with the child soldiers, like Nabuca and Tabool, is one of a cruel master who has broken their wills and forced them to fight for a cause they do not believe in, often through lies about eventually allowing them to return home. His obsession with Lala-Ru is a grotesque one, as he alternates between threatening her friends to force her cooperation and whining and pleading with her like a petulant child.

Hamdo undergoes little to no positive development or redemption. Instead, his arc is one of escalating desperation and a final, pathetic collapse. As his plans fall apart, his mental instability becomes more pronounced, and his cowardice is laid completely bare. In the climax, when Lala-Ru finally unleashes her power and floods Hellywood, Hamdo completely abandons his post and his followers, begging Abelia to save only him and transport him to another world. His story ends not with a noble final stand, but with him being brutally beaten by the teenage protagonist Shu with a wooden stick. He is last seen fleeing in terror, crying and screaming, before drowning in the floodwaters of his own collapsing empire, a final, undignified end for the mad king.

Regarding notable abilities, Hamdo possesses no special powers or remarkable combat skills. He is not a warrior and relies entirely on his army and his fortress for his power. His primary "ability," if it can be called that, is a capacity for extreme cruelty and psychological manipulation. While he is shown to have knowledge of military theory, he is completely ineffective at applying it, leaving all strategic command to his subordinate Abelia. His power is derived entirely from his position and the fear he instills in others, not from any personal strength or talent.