Daisuke Yamori, also known by his LaMetal name La Els Milliue, is a character whose life is defined by a profound conflict of allegiance. He arrives on Earth as an underling of Queen Millennia, who is living under the human name Yayoi Yukino, and for a thousand years, he accompanies her on her hidden reign, serving as her assistant. His lineage has a longstanding connection to the Millennial Queens, as earlier generations of his family served as their protectors. Physically, he is recognized by his green hair and either black or blue eyes.

Outwardly, Yamori operates as a dedicated assistant to Yayoi, but this role masks a secret and treacherous duty. He has pledged allegiance to the LaMetal forces and reports to Dr. Fara, the commander of LaMetal's Earth operations. This dual loyalty creates an underlying tension that escalates as Yayoi begins to resist LaMetal's agenda for Earth. His personality is often described as taciturn, passionate, and brave, possessing a spirit of sacrifice. However, he is also characterized by a deep-seated jealousy and prejudice against human beings. His internal conflict is immense; he finds himself torn between his loyalty to the queen he has served for a millennium and his duty to his home planet in the growing conflict between LaMetal and Earth.

Throughout the story, Yamori withholds his knowledge of LaMetal's true intentions from Yayoi, including the revelation that the prophesied planetary collision is a fabricated scenario designed to displace humanity and allow for colonization. Despite their long association, he keeps these secrets, even as he demonstrates an unrequited affection for Yayoi that is secondary to his role-driven actions. His motivations are rooted in this divided loyalty, and his primary role in the narrative is that of a conflicted figure whose secret actions directly impact the queen and the fate of Earth.

The decisive turning point for Daisuke Yamori occurs when open conflict erupts between Earth's defenders and the LaMetal invasion fleet. After Yayoi explicitly refuses to cooperate with the takeover, Yamori is forced to make a choice. In a critical moment, he declares that his loyalty lies solely with her, rejecting Dr. Fara's authority. His development culminates in a sacrificial act of redemption; he pilots his aircraft directly into Dr. Fara's flagship, inflicting significant damage on the enemy vessel. This act results in his death but marks a complete and final break from his obligations to LaMetal, as he ultimately sides with Earth and the woman he served despite his origins. In terms of notable abilities, Yamori is shown to be a capable pilot, demonstrated by his critical flying maneuver in the final battle.