Gourry is a wandering swordsman who encounters Lina in the first episode of the television series, and he continues to accompany her from then on. He wields the legendary Sword of Light, originally known as Gorun Nova before it arrived in the Slayers world. Gourry lacks scholarly pursuits and seems to have significant memory issues along with ADD, but his swordsmanship skills are unparalleled within the franchise. His manga profile describes him as "as loyal as man's best friend but not quite as smart." After meeting Lina, he decides to become the "little girl's" unpaid bodyguard (despite being disappointed by his charge's lack of physical development), and they gradually get to know each other. Throughout the franchise, Gourry's kindness (he spares his rival Zangulus' life on multiple occasions), loyalty (absolute to Lina), and consideration for others are evident, though not as idealistic as those of the Seyruuns.
While Gourry is formidable with ordinary steel, he becomes incredibly powerful when armed with his family's magic blade. He is the guardian of the Sword of Light, a mystical weapon whose steel blade can be detached, allowing the use of an alternate blade made of pure, destructive light powered by sheer will. The sword can defeat lower-ranked demons on its own and absorbs magic. If magic is cast directly onto the Sword of Light, its power merges with that of the spell. Gourry takes great care of the Sword of Light, watching it closely to protect the valuable relic from thieving hands, particularly those of Lina herself. Lina frequently tries to trick him into giving it to her by claiming he already promised it to her, but these are one of the few times where Gourry's usually unreliable memory is crystal clear. Gourry does allow Lina to borrow the sword in certain extreme circumstances.
At the end of the third series, Gourry relinquishes the Sword of Light so that it and other light weapons can be protected. In the following book series, he acquires the legendary Blast Sword. By manipulating the magical energies around it, the Blast Sword creates an extremely sharp blade. If not treated with care, it can slice through its sheath and sink up to its hilt into the ground below. An enchantment placed on it by the party allows them to adjust its sharpness for practical use. Eventually, Gourry falls in love with Lina. Although he is less shy about the concept than the young sorceress, he apparently doesn't know how to make a romantic advance—yet another thing Gourry doesn't know.