Slayers Royal is notable for bringing together Naga the Serpent (Lina Inverse's companion in the prequel stories) with Gourry Gabriev, Amelia Wil Tesla Seyruun and Zelgadis Greywords (Lina's companions in the main storyline) at once for the first time. In the game's storyline, Lina, Gourry and Naga encounter an elf boy named Lark (ラークの) being attacked by the mazoku demons. After rescuing him, they find that the mazoku have kidnapped Lark's sister in order to gain an ancient amulet that is now in hands of Lark. Eventually, they discover the real power of this legendary relic: with it, the mazoku can resurrect the demon king Ruby-Eye Shabranigdu and destroy the world.