Subaru Natsuki hails from Japan, where he lived as a high school student and self-described NEET prone to social withdrawal. He is the son of Kenichi and Naoko Natsuki. His past includes kendo practice and maintaining basic fitness, granting him foundational hand-to-hand combat skills and parkour knowledge, though he lacked exceptional physical prowess. His life took a drastic turn when transported to the fantasy world of Lugunica by Satella, the Witch of Envy, while returning from a convenience store. Physically, Subaru possesses short black hair, brown eyes, and an average build, standing 173 cm (5'8") tall. He first appears in a black-and-white tracksuit with orange accents, later adopting butler attire during his service at Roswaal Mansion. By Arc 6, his outfit changes to a green jacket, light brown shirt, black pants, and an orange scarf. His eyes are occasionally noted for an "evil gaze" due to his "sanpakugan" (three-white sclera appearance). Subaru's personality undergoes significant evolution. Initially marked by impulsive arrogance, a tendency to avoid difficulty, and an obsession with being perceived as a hero, he develops an intense, almost possessive devotion to Emilia after she saves him from thugs in Lugunica. This leads to decisions made without considering consequences or others' perspectives, culminating in a public humiliation incident where he disrupts a royal selection ceremony to defend her, straining their relationship. His psychological state deteriorates under the repeated trauma of death and resurrection via his ability "Return by Death," manifesting in phases of rashness, paranoia, and despair. A pivotal turning point occurs in Episode 18 when Rem's unconditional support and confession help him confront his flaws—selfishness, entitlement, and cowardice—reigniting his resolve to protect others without expecting rewards. Subsequent arcs showcase increased resilience, strategic thinking, and self-sacrifice, such as taking on others' burdens via the Authority of Greed. Despite this growth, remnants of his impulsivity and self-doubt persist. Subaru's primary ability is "Return by Death," granted by Satella. This power returns him to a predetermined "save point" upon death, retaining his memories. The save points shift unpredictably, and disclosing the ability triggers Satella's miasma, attracting malevolent entities or causing harm to those nearby. The repeated deaths inflict severe psychological trauma, contributing to instability. He also possesses two Authorities derived from Witch Factors: - **Authority of Sloth (Invisible Providence)**: Obtained after Petelgeuse's death, manifesting an invisible, intangible hand for limited physical interference. - **Authority of Greed (Cor Leonis)**: Acquired after defeating Regulus, allowing him to absorb physical or mental burdens from emotionally bonded allies, temporarily enhancing their capabilities. Subaru can use Yin Magic, primarily "Shamak," which creates disorienting darkness. After his "gate" (mana-regulation organ) ruptured in Arc 4, he became dependent on the artificial spirit Beatrice for mana management. Their contract enables combined spells like "E・M・M" (absolute defense barrier) and "E・M・T" (mana-negation field), each usable once daily. Additional skills include spirit affinity, basic whip combat, and parkour learned post-Arc 4. His mount, Patrasche, is a loyal black Earth Dragon gifted by Crusch. Relationships are central to Subaru's development: - **Emilia**: He dedicates himself to protecting her after she saves him in Arc 1. His unrequited love drives many actions, though his initial possessiveness strains their bond. Their relationship gradually mends through mutual sacrifice. - **Rem**: Her unwavering faith becomes his emotional anchor after her confession in Arc 3. She repeatedly sacrifices herself for him across timelines, solidifying their deep, reciprocal loyalty. They agree to pursue a polygamous relationship with Emilia, though Rem falls into a coma in Arc 4. - **Beatrice**: Their contract forces mutual dependence, with Subaru supplying her mana. Initially antagonistic, their dynamic evolves into genuine partnership, exemplified by collaborative magic. - **Others**: He forges alliances with Crusch and Reinhard after aiding in defeating the White Whale. Ram nicknames him "Barasu" (trash) but acknowledges his value. His rapport with spirits like Puck remains amicable despite past conflicts. In extended media like the XP4 fanfics, Subaru appears as a student at AWA Academy and a member of Team Idolo in the Heroes Coalition. Light novels depict him traveling to Vollachia with Rem and Louis Arneb under unclear circumstances. Alternate timelines (e.g., "Re:Zero Rem What If") show him with long hair and a kimono, while the "Tsugihagu" scenario depicts him with white hair and a blinded eye after interacting with the Books of the Dead.