Krest Saber Hargen is a pilot and key member of the Sonic Diver team, delivering vital air support to the AEGIS organization. He actively engages in defensive operations against threats. Initially projecting extreme confidence bordering on arrogance, Krest frequently disregards orders, opting for high-risk maneuvers that reflect his self-assured combat style.

The defining event in his past is the loss of his younger sister during an enemy attack. This personal tragedy fuels a deep-seated drive for vengeance against those responsible, profoundly shaping his motivations and aggressive focus during missions.

Over time, interactions with teammates reveal layers beneath his reserved exterior. Despite this detachment, Krest develops a strong protective instinct towards his fellow pilots, repeatedly risking his own safety to ensure their survival. This shift marks an evolution from individualistic pursuits towards valuing collective security and camaraderie.

In combat, Krest's operational style emphasizes practicality and rapid assessment. He relies on quick reflexes and sharp analysis to counter emerging threats, consistently prioritizing immediate tactical solutions over broader strategy or emotional considerations. This approach can spark friction, especially in missions demanding greater collaboration on complex social or emotional fronts.

Krest maintains a composed, controlled exterior under pressure, rarely showing overt emotion even in intense engagements—a stoic hallmark of his professional identity as a pilot. Yet, his fierce commitment to protecting teammates and pursuing justice for his sister reveals deeper convictions far beyond mere duty.