Kento Yūki is a seemingly ordinary fourth-grade student in the year 2100, where children upload their consciousness as Web Divers. In the physical world, he displays no remarkable talents or academic prowess and occasionally causes minor troubles. This mundanity starkly contrasts his capabilities within the global computer networks. He narrowly escapes capture during a catastrophic virus attack on the cyber park Magical Gate, which traps and brainwashes other children. This makes him the sole human ally to Gladion, the only Web Knight unaffected by the virus. Gladion selects Kento as his pilot to combat the viral entity Deletloss and rescue the corrupted children.

Within the network, Kento reveals exceptional piloting skills and innate leadership. His deep care for friends extends to both humans and sentient Web Knights, forging strong bonds with programs like Gladion. He spearheads the recruitment of additional pilots from rescued children, including his childhood friend Naoki Asaba and senior student Shō Kurachi. Kento's protective instincts intensify upon learning his younger brother Kaito is among the trapped. This personal stake drives him to persist despite extreme danger, though he initially resists allowing Kaito to participate in battles.

Kento's development involves escalating challenges. He coordinates complex combination attacks using Gladion's fusion capabilities with other Web Knights like Griffion and Phoenixon. His partnership evolves into Victory Gladion when fusing with Kaito's Wyverion, triggering physical transformations like white wings and altered diver suits. During the final confrontation with Deletloss, Kento witnesses Gladion's near destruction and subsequent amnesia. He undertakes a perilous dive into Gladion's spiritual world to restore the Web Knight's memories through an emotional connection. Their ultimate union manifests Kento and Gladion as a unified cyber datanoid resembling an angelic entity to defeat Deletloss.

Persistent loyalty defines Kento, repeatedly prioritizing others' safety above tactical advantages. His growth culminates in accepting Kaito's role as a pilot and trusting allies like Shō with pivotal responsibilities. The collective hope of rescued children, channeled through the AI Ange, empowers Kento and Gladion during their climactic battle.