In a world where individuals possess eight skill slots for abilities like 'Strengthen arm' and 'Fire Magic,' Reiji toiled as a slave mining skill orbs alongside his cherished older sister, Larc. Their lives changed when Reiji acquired a rare ten-star skill, the 'World Ruler,' during a rebellion in the mines. Empowered beyond imagination, Reiji lost Larc in the chaos, spurring him on a quest to reunite with her and redefine their sibling bond. Thus, Reiji embarks on a journey to distant lands, seeking to make his sister truly his own.