Delta is a central character in the anime Kage-jitsu, serving as a prominent member of the elite operatives known as the Seven Shadows within the clandestine organization Shadow Garden. Her past name was Sara, and she is a young female beastkin, typically depicted as being between thirteen and fifteen years old. As a beastkin, she possesses distinctive wolf-like features, including long black hair, large wolf ears on top of her head, and a thick tail.

Personality-wise, Delta is defined by her wild, instinctual, and power-oriented nature. Her behavior is often described as excitable and immature, akin to a child, and she has a tendency to refer to herself in the third person. She places immense value on strength above all else, a common trait among beastkin but one that is exceptionally pronounced in her. Consequently, her loyalty is not given freely but is reserved for those she deems powerful, such as her master Cid Kagenou, whom she respectfully calls Boss, and the leader of Shadow Garden, Alpha. She holds open contempt for those she considers weak and has no qualms about disregarding or dominating them, as seen in her rivalry with her fellow Seven Shadows member Gamma. Her impulsiveness is a major facet of her personality; she finds waiting to be extremely difficult and prefers to charge into battle immediately. Despite her ferocious and sadistic demeanor towards enemies, leaving none alive, she shows a deep, almost childlike affection for her master, often hugging him excitedly upon meeting. She also possesses very little sense of shame, a trait humorously highlighted when her combat suit is damaged, leaving her to fight in makeshift, revealing armor without any apparent embarrassment.

Delta's motivations are rooted in a combination of gratitude and a primal drive to follow strength. Her life was saved and her health restored by Cid Kagenou, which forms the basis of her profound thankfulness and loyalty to him. Beyond this, her actions are driven by a simple, pack-like mentality where she views Shadow Garden as her pack with Cid as its undisputed leader. She does not concern herself with the organization's grander ideals or complex strategies, finding her primary motivation in the joy of the hunt and the opportunity to prove her strength in battle. This focus on strength was forged by a tragic past; she was once a sweet girl who cared for her sick mother but suffered abuse from the rest of her family. After her mother's death, her personality radically transformed into the bloodthirsty and wild warrior seen in the present. Her backstory also reveals she was exiled by her pack, and she holds a deep hatred for them for this reason, which may contribute to her rejection of weak family bonds, as she showed no hesitation in killing her own brother whom she considered weak.

In the story, Delta's role is primarily that of the organization's main combat force and a specialist in search-and-destroy missions. She is recognized as the third-strongest member of Shadow Garden, with her raw physical power being second only to Shadow himself. However, her lack of intelligence and self-control makes her a blunt instrument, most effective when simply pointed at an enemy to be eliminated. She is utilized for her unparalleled tracking abilities and her capacity to unleash overwhelming force, rather than for tasks requiring subtlety or complex planning. An example of her straightforward approach is seen when she accidentally destroys a valuable magical artifact simply by demonstrating her physical strength, creating a shockwave that shatters it.

Her key relationships are defined by the hierarchy of power she respects. Her most significant bond is with Cid Kagenou, whom she views as the ultimate leader of her pack. She is unconditionally devoted to him, and her loyalty is so absolute that she can recognize him through any disguise, relying on her superhuman sense of smell. Her relationship with Alpha is another crucial one; she respects Alpha's strength and intelligence, and Alpha is one of the few people who can control her, often needing to use intimidation or threats to snap Delta out of a combat frenzy. Conversely, she has a long-standing rivalry with Gamma, whom she sees as weak and openly dominates in practice, though there remains a foundational layer of care between them as fellow members of the original Seven Shadows.

While Delta does not undergo a significant personality shift, her development is shown through the deepening of her loyalty and the revelation of her tragic past, which provides context for her present-day ferocity. Her history of caring for her dying mother contrasts sharply with her current bloodthirsty nature, illustrating how trauma and a beastkin's survival instincts reshaped her.

Delta's notable abilities make her an exceptional combatant. Her most prominent asset is her immense physical strength, which is the highest among the Seven Shadows and second only to Shadow's. This raw power allows her to perform feats like slicing entire buildings in half with a single swing of her weapon. She complements this strength with superhuman beastkin senses, including an extraordinary sense of smell, hearing, and sight that surpass even Cid's, making her an expert tracker. In combat, she wields a massive greatsword she calls the Iron Clump, or uses her slime bodysuit to form powerful claws, favoring a fighting style described as raw violence that relies on instinct and brute force over technique. She can also enter a fearsome state known as Hunter's Frenzy, which makes her far more aggressive and virtually impossible to stop until her targets are destroyed. Although she lacks finesse with magic and cannot cast complex spells, she possesses an extraordinarily high amount of magical energy which she instinctively channels to further enhance her physical attacks to devastating levels.