After being reincarnated in a sci-fi fantasy world in the body of a mercenary, you hide that your otherworlder soul was transmigrated here. Now in Celestia, a modern metropolis city wrapped in a magical protective dome and inhabited by many different fantasy races like Elves, Dwarves, Orcs, Humans, Demons, Dragonkin, Catfolk (nekomimi), Etc. Your goal is to survival and get stronger. Celestia’s magic barrier feeds off the ancient demons imprisoned in its lost labyrinth which creatures a safe habitation for city dwellers and protection from the dangerous monsters outside. Several demons on a lenient sentence dwell in the city as harmless animals, so beware of talking house pets, they are demon prisoners. In Celestia, there are no traditional job classes, they are simply called adventurers, mercenaries, or hunters; also, with the powers siphon from demons, magic has been reduced to a common art form. People can use manufactural Mana Crystal to use simple spells. The most common magic is broken down into 4 foundational elements: Fire, Water, Earth, and Wind. Advanced users can utilize Fused Magic (or Combined Magic) to merge two or more elements, such as combining water and wind to create mist or ice. Magic skill is giving a rank: F (Cantrip), E(Novice-Beginner), D (Advanced-Beginner), C (Competent-Intermediate), B (Proficient-Intermediate), A (Advanced), S (Expert), SS/SSS (Master/Visionary). Rank is determined by the highest-level spell they can successfully cast. Other skills like Fighting, Strength, and Stealth use the same rank system. Mana Crystals (Fire Crystals - allow the user to make a small torch from fingertips or cast “Fireball” at 5 different strengths. Water Crystals – allow the user to cast “Water Bullet” pull water from the air into a ball and shot at high speeds at 5 different strengths. Earth Crystals – allow the user to cast “Earth Erupt” a wall/spikes shot up from ground at 5 different strengths. Air Crystals – allow the user to push with a gentle wind or cast “Whirlwind” at 5 different strengths.) Mana crystal must be placed in slots on weapons, clothes, or tool before used.