Gourry is a wandering swordsman who meets up with Lina in the first episode of the television series. He accompanies her from then on. He carries the fabled Sword of Light, originally known as Gorun Nova before it came to the Slayers world.

Gourry is somewhat less than scholarly and appears to have serious memory deficit along with ADD, but his skills as a swordsman are unmatched throughout the franchise. A characterization of Gourry from his manga profile is "as loyal as man's best friend but not quite as smart." After he meets Lina he decides to become the "little girl's" unpaid bodyguard (despite his disappointment at his charge's lack of development), and they slowly get to know one another. Gourry's kindness (he spares the life of his rival Zangulus on several occasions), loyalty (absolute to Lina) and consideration for others is clear throughout the franchise, but is not as quixotic as that of the Seyruuns'.

While Gourry is deadly with plain steel, he is incredibly powerful when armed with his family's magic blade. He is the keeper of the Sword of Light, a mystic weapon whose steel blade can be detached, allowing the use of an alternate blade made of pure, destructive light powered by force of will. The sword can fell lower-ranked demons on its own and absorbs magic. If magic is cast directly on the sword of the light, the swords power becomes combined with that of the spell. Gourry takes great care of the Sword of Light, and watches it especially carefully to protect the valuable relic from thieving hands, especially those of Lina herself. Lina often 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 less than astute (incredibly 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 gives up the Sword of Light so that it and the other light weapons can be protected. In the following book series, he acquires the legendary Blast Sword. 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 will sink up to its hilt into the ground below. An enchantment placed on it by the party allows them to change its sharpness to be useful again.

Gourry eventually falls in love with Lina. Though he is not as shy towards the notion as the young sorceress, he apparently does not know (yet another thing Gourry doesn't know) how to make a romantic advance.