Rimuru Tempest began existence as Satoru Mikami, a 37-year-old Japanese salaryman reincarnated into a fantasy world as a slime after dying to protect a colleague. This rebirth granted the unique ability "Predator," enabling the consumption and replication of other beings' forms and skills. The name "Rimuru Tempest" came from the Storm Dragon Veldora, whom Rimuru discovered sealed in a cave shortly after reincarnation. After pledging to analyze and break Veldora's seal, Rimuru consumed him, initiating a symbiotic relationship that deepened into a familial bond. Rimuru's slime form manifests as a spherical, translucent blue ooze, initially around 40 cm in diameter, expanding to approximately 80 cm upon evolving into an Ultimate Slime. This form can adopt a metallic look via the "Body Armor" skill and exhibits a golden sheen as a Demon Slime. Rimuru's human form, acquired by consuming the deceased adventurer Shizue Izawa, progresses through distinct stages: first resembling a child aged 6-7 years; evolving to a pre-teen form after consuming the Orc Disaster Geld; shifting to an adolescent form upon becoming a True Demon Lord; and finally, as an Ultimate Slime, presenting as an androgynous 15-16-year-old with silver-blue hair, golden eyes, and delicate features. Clothing evolves from simple pelts to sophisticated attire like black pants, sleeveless shirts with gold accents, and a haori or cloak. Rimuru is canonically genderless, reflecting a deliberate authorial choice to avoid gender assignment. Rimuru's personality merges Satoru Mikami's human pragmatism with a slime's adaptive nature. Outwardly laid-back and eccentric, Rimuru prioritizes building a comfortable world where all beings coexist peacefully. Internally, constant strategizing favors long-term benefits over emotional reactions, sometimes employing forged documents or memory alteration to maintain a benevolent image. Yet Rimuru displays ruthless brutality against threats to subordinates or Tempest, viewing them as family. Core motivations involve avoiding unnecessary conflict while driving societal progress through infrastructure, trade, and diplomacy. Abilities expand dramatically through evolution. Initial skills include "Predator" (later upgraded to "Soul Consumption" for soul absorption), "Great Sage" (analytic and replication capabilities, evolving into "Manas: Ciel" for advanced skill copying), and "Magic Sense" (translation and environmental awareness). After evolving into a Demon Slime, Rimuru gains the power to shift between material and spiritual forms, a tenfold increase in magical energy, and techniques like space-time manipulation. As an Ultimate Slime and True Dragon, abilities encompass "Turn Null" (generating destructive void energy), "Space Time Control" (instantaneous movement across dimensions), "Multi-Dimensional Barrier" (absolute defense), and "Suspended World" (cognitive acceleration). Combat proficiency blends sword mastery from Hakurou's training with diverse magic, including summoning and golem creation. Rimuru's development includes founding the Jura Tempest Federation, starting as leader of a goblin village before expanding into a nation uniting monsters and humans. Key milestones involve evolving into a Demon Lord via the Harvest Festival to resurrect slain subordinates, establishing diplomatic ties with human kingdoms, and joining the Octagram demon lord council. Leadership focuses on societal advancement through technology, education, and cultural integration, reflecting Satoru's Earth-inspired ethics. Relationships span familial bonds with Veldora and subordinate monsters like Shuna and Benimaru to strategic alliances with figures such as Elmesia of Sarion. In the upcoming "Soukai no Namida-hen" film, Rimuru and Tempest officials vacation on Sarion's resort island at Elmesia's invitation. This respite shatters with the appearance of a mysterious girl named Yura and an emerging threat, drawing Rimuru into a new conflict outside prior light novel or manga arcs. The story occurs after Tempest's founding celebration, highlighting Rimuru's diplomatic and protective roles in maintaining stability. Rimuru's background as Satoru Mikami provides a unique perspective, merging human ingenuity with monster capabilities to redefine power structures. The journey from solitary slime to nation-building leader underscores themes of reincarnation, identity, and pragmatic idealism.