Suguru stands as a close companion to the protagonist, completing the trio alongside Mio. His deep knowledge of fish species and behaviors makes him a vital informational resource on fishing expeditions. Technically adept, he designs and constructs specialized fishing lures, crafting many of the protagonist's essential lures in the initial series and later developing custom lures for BB in the RV sequel.

He demonstrates unwavering loyalty within the group, readily offering assistance despite occasional disagreements with the protagonist. This supportive nature shines during critical moments, such as when he provides encouragement to Yun, who fears the nature of a newly acquired Legender. While generally characterized by camaraderie, Suguru harbors a distinct romantic affection towards BB, one of the protagonist's rivals. This consistent interest colors their interactions, though it never solidifies into a confirmed relationship.

His involvement proves integral during the group's global travels, both in the initial quest against antagonistic fishing forces and the subsequent RV journey to locate mythical Legenders. He actively confronts rivals employing unethical methods, yet he never obtains a Legender himself. His primary contributions remain his technical expertise in lure creation and his steadfast presence within the core group throughout their adventures.