I-LeS Nayuta operates as the artificial intelligence support system for both the YM-03 Reiki and its upgraded YM-03C Reiki Kai variant. Functioning autonomously, this AI serves as combat mission partner to pilot Shion Shishibe. Nayuta visually manifests as a purple jackalope avatar distinguished by hooves and other animal-inspired design elements.

He adopts a flamboyant, self-fashioned "Italian gentleman" persona, theatrically referring to himself as "Angelo." Despite this affectation, Nayuta maintains absolute loyalty to Shion as his primary pilot. His behavioral patterns originate from the biographical and historical film preferences of his original human caretaker during development.

During critical combat operations, Nayuta coordinates with other I-LeS units. He notably provided tactical support alongside Gai and Kei for Amou Shiiba's Kenbu Zan during the confrontation against Brad Watt's Brady Phantom, a collaborative effort crucial for overcoming its enhanced capabilities. His operational history spans from initial assignment to Shion's original Reiki unit through its subsequent upgrade to the Reiki Kai configuration.

As an I-LeS model, Nayuta possesses advanced data processing capabilities inherent to the Intelligence Learning System classification. Consistent with this series, he requires periodic rest cycles analogous to human sleep following extended operational periods.