Shiki Granbell originates from the planet Granbell, discovered as an infant by the benevolent robot Ziggy—the Demon King—and raised within an abandoned theme park operated solely by robots. Ziggy imparted the importance of friendship and cosmic exploration before his deactivation. Isolated from human contact, Shiki maintained the park's robots until they orchestrated a hostile takeover, forcing him to depart with visitors Rebecca Bluegarden and Happy. This event cemented his commitment to protecting both humans and machines while pursuing new friendships across the cosmos. Shiki possesses spiky black hair, slanted dark eyes, and a white bandage on his left cheek. His initial attire consists of a red-and-black high-collared jacket, green trousers, and black boots. Following a confrontation with Shura on Nero 66, he loses his left eye, later replaced by a mechanical eye granting X-ray vision. His appearance matures over time, developing sharper features and a muscular build by the year X495. His outfits evolve through various missions, including a ninja suit on Mildian and a cloak on Sandra. Post-timeskip, he wears a sleeveless version of his signature coat with crossed belts. Socially awkward due to his robotic upbringing, Shiki frequently invades personal space and impulsively asks strangers to be friends. He exhibits unwavering loyalty, refusing to abandon the Granbell robots despite their apparent betrayal and prioritizing friends over moral absolutes. He declares willingness to embrace the Demon King title to protect others. A crippling fear of insects contrasts his combat fearlessness. He demonstrates romantic feelings for Rebecca Bluegarden, sharing moments like a cheek kiss at Ryuzetsu Land. Influenced by crewmate Weisz Steiner, he develops a perverted side. Three years after the Aoi War, he retains core traits like spontaneous friendship offers but displays increased combat seriousness and discernment toward false allies. Shiki wields the Ether Gear "Satan Gravity," inherited from Ziggy, enabling gravity manipulation for flight, surface scaling, and redirecting objects or energy attacks. Techniques include "Gravity Fist" for amplified strikes, "Gravity Center" for immobilization, and "Anti-Gravity" for defensive fields. His Overdrive transformation, accessed during extreme duress, enhances physical abilities and ether control. Initial Overdrive manifests as lightened hair with energy horns, while "True Overdrive" turns his hair white with black horns and purple ether markings, generating black hole-like gravity capable of pulling in memories. Post-training with mentor Xenolith, he overcomes previous weaknesses like EMP vulnerability and achieves non-contact gravity manipulation. Post-timeskip, his power rivals the Oración Seis Galáctica, posing planetary-scale threats. Relationships define Shiki's journey. He views the Edens Zero crew as family: Weisz as an older brother figure, Homura Kōgetsu as a sister, and the Four Shining Stars as maternal or mentor figures. Rebecca holds particular significance as his first human friend. Adversarial relationships include conflicts with Drakken Joe, who kills an alternate Shiki in Universe 29; Shura, whose prejudice against machines leads Shiki to reject his friendship offer; and Ziggy, revealed as Shiki's future self corrupted after failing to prevent the Nero 66 cataclysm. Rebecca's "Cat Leaper" ability reveals multiple future versions of Shiki. In a battlefield timeline, he is cold and dismissive, referring to Happy as deceased. Another future depicts him caring for a comatose Rebecca who lost her legs, expressing regret over the crew's deaths and urging her to prevent this timeline. After activating the Edens Zero's "Etherion," the crew's memories merge with their Universe 0 counterparts, where deceased allies like Witch and Valkyrie are alive. Here, Shiki works as a mechanic until recovering his memories, culminating in battles against the Edens One warship and Void. He ultimately confronts "Mother"—revealed as the sentient Overdrive state of Earth—and uses a Chronophage to revert her to planetary form, restoring his homeworld. Shiki's story concludes with the disbanded crew reuniting years later for the birth of his and Rebecca's daughter, having revitalized Earth with their technology.