Surarin is a slime encountered and named by Luca during his escape from a decade of enslavement alongside Prince Harry. Luca, his sabrecat Purrcy, and his father's retainer Sancho discovered this companion during their travels. Surarin possesses the classic slime form: an onion or raindrop shape, round eyes, and a permanent, toothless smile.

Surarin remained with Luca's group through subsequent adventures, including the battle against Bjørn the Behemoose and Luca's marriage to Bianca. During a critical confrontation with a reality-disrupting entity identifying itself as a computer virus within a simulated Dragon Quest V, Surarin revealed a hidden function as an embedded anti-virus program. This revelation repositioned Surarin as a protective mechanism within the simulation, not merely a companion.

To counter the virus threatening to erase the simulation, Surarin provided Luca with Erdrick's Sword. Luca used the weapon to destroy the virus and restore the game's intended narrative. Surarin's involvement concluded after this restoration, when Luca's party arrived at Gotha to view fireworks. In English-language adaptations, this character is also identified as Gootrude.