Julian Ainsworth inherited the position of head within the Ainsworth family following the death of his sister, Angelica Ainsworth. Angelica was originally intended as the vessel for their ancestor, Darius Ainsworth; her demise during the Fourth Ainsworth Holy Grail War forced Julian himself to become Darius's vessel at approximately eleven years old. This transformation marked a significant turning point, burdening him with fulfilling the family's legacy. He possesses short black hair and blue eyes, previously concealed by thin glasses during his school days. Prolonged stress left noticeable bags under his eyes. Initially appearing in a Homurahara School uniform, Julian discarded his glasses entirely upon discovering Shirou Emiya's role in hiding Miyu Edelfelt, symbolizing the end of their friendship. Confronting his world's impending death, Julian dedicated efforts to locating Mystic Codes, magical implements, and vessels capable of replacing Noble Phantasms and the Holy Grail. After numerous failures, he oversaw the creation of Miyu Edelfelt as a functional Holy Grail designed to save the world. This plan required sacrificing Miyu to ascend humanity into beings capable of surviving the new world. Miyu's brother, Shirou, opposed this and facilitated her escape to another world, leading to Shirou's capture as leverage. The process halted until Gilgamesh's Enuma Elish reopened a path between worlds, enabling Miyu's recapture by Angelica and Beatrice Flowerchild. Julian maintains a serious demeanor, though earlier photographs suggest a less severe personality. He operates under the conceptual replacement of Darius Ainsworth, adopting the ancestor's identity. Miyu labels him a "counterfeit clinging to a ghost," a description that angers him as he insists he *is* Darius. He claims his primary goal is saving the world and fulfilling the Ainsworth wish alongside his foster sister, Erika. This involves crafting his own legend, necessitating Miyu's sacrifice. Shirou identifies Julian as a "Champion of Justice" for prioritizing the greater good over one life, contrasting with those who aim to save the individual. Julian accepts that stopping him requires embracing associated evils. He perceives the world's events as a staged performance for his legend, fixated on dramatic presentation. Individuals around him are "players" with predetermined roles. He casts figures like Illya and Tanaka as critical to his narrative and avoids eliminating them prematurely. Conversely, he harbors intense hatred for Shirou, whom he views as an unnecessary disruption. Before Miyu's capture, Julian displayed traits of a typical teenager. He maintained a casual, albeit strained, friendship with Shirou, often appearing rude and dismissive of casual conversation, which he deemed pointless. He exhibited a short temper, snapping easily, particularly at Shirou. He prioritized saving his sister over the world if forced to choose. His personality shifted dramatically upon learning Shirou hid Miyu, feeling profoundly betrayed. Beneath his calculated exterior lies deep-seated torment. Angelica revealed Julian harbors hatred toward Darius due to the ancestor's role in Erika's suffering, a resentment that intensified over time. In the events leading to *Licht - The Nameless Girl*, Julian, as Darius, first intervened when Illya, Gilgamesh, and Tanaka attempted to rescue Miyu. He halted Beatrice's use of Mjölnir and politely introduced himself as the family head. Later, infiltrating Illya's temporary base under the pretense of thanking her for watching Erika, he declared himself the "demon king" Illya must kill when identified as a threat. He trapped Illya and her allies within a barrier called Apneic Beauty, showcasing his flair for theatricality. Annoyed by Tanaka's interference—an "extra" disrupting his stage—he subdued the group with Authoritarian Personalism but spared them, declaring the Sixth Holy Grail War resumed. He regularly extracted Miyu's blood to inscribe his legend onto tablets, using threats against Shirou to ensure her compliance. When Erika orchestrated Illya's kidnapping to appease Miyu, he reacted with rage upon learning it risked his narrative. Miyu's suicide threat over Illya's safety prompted him to project battlefield images to her, aiming to induce despair. Illya's resolve to save both Miyu and the world instead amused him, as he viewed such hope as "the deadliest of poisons" for Miyu. Illya's use of Rule Breaker dispelled Darius's conceptual duplicate, exposing Julian and collapsing the estate's protective Bounded Fields. Enraged by Miyu's escape and loss of leverage over Shirou, Julian summoned a massive cube structure. He asserted his legend's inevitability, dismissing others' actions as mere ingredients for his story. Angered by Miyu's "counterfeit" accusation, he destroyed the Caster Card. He assured Erika of their shared mission, prompting her to activate the cube, which unleashed corrupted Heroic Spirits to pursue Miyu. He tempted Miyu with ending the despair only her return could halt, a ploy interrupted by Shirou's arrival and declaration of war.