Oscar is a human teenager with distinctive red hair and blue eyes, hailing from a wealthy background. He is bound by his families' arranged childhood engagement agreement to Grace. Oscar's intense fascination with extraterrestrial life drives him to actively investigate rumors of alien activity near Mariel's residence.

This persistent investigation leads Oscar to discover Memole's existence. After proving trustworthy, he becomes one of the few humans, alongside Mariel and eventually Grace, entrusted with the secret of the Riruru aliens. He functions as a mediator between the human and alien groups, facilitating communication and cooperation.

A close bond develops between Oscar and Mariel, marked by mutual support and romantic undertones. This relationship creates tension with his arranged engagement to Grace. His initial obligation to Grace evolves following her traumatic accident and memory loss. During her recovery, Oscar provides consistent support, contributing to Grace's reconciliation with Mariel and his own gradual shift toward resolving the love triangle amicably.

Throughout the series, Oscar demonstrates adaptability in navigating complex social dynamics, balancing familial expectations with his personal connections to Mariel and Memole's community. Driven by scientific curiosity, his role transitions into a protective one toward the Riruru inhabitants, aiding efforts to maintain their secrecy.

The resolution of his character arc involves acknowledging Grace's enduring feelings while prioritizing Mariel's well-being, culminating in peaceful coexistence among all parties. His development reflects a transition from privileged obligation to genuine emotional maturity.