Momo Saiga, known in the game Shangri-La Frontier as Psyger-100, is the older sister of Rei Saiga, who plays as Psyger-0. In the real world, she is a hardcore gamer who dedicates much of her free time to the virtual reality world, often spending entire days logged in. She is the founder and leader of the clan Schwarzer Wolf, a group she established with the ambition of hunting and defeating the Colossus Lycagon the Nightslayer.

Her appearance contrasts with her younger brother; she has brown hair, blue eyes, and a more intimidating stature, standing 179 centimeters tall. Her in-game avatar reflects her status as a formidable player, and she wields both the Sword Saint and Hero classes, demonstrating her versatility and high skill level.

Personality-wise, Momo is intensely focused and serious about her gaming endeavors, often perceived as daunting by others. Despite this, she is not antagonistic by nature; her drive comes from a deep enjoyment of the game and a competitive spirit. She maintains a friendship with Towa Amane in real life, indicating a sociable side outside of the game.

Within the story, she initially appears as a minor antagonist, but her role is more that of a rival player with her own objectives. Her relationship with Rei is significant, as they are siblings, yet they often pursue different paths within the game. Her development is subtle, centering on her dedication to Schwarzer Wolf and her personal goals, making her a respected and powerful figure among the player base. Her notable abilities stem from her mastery of the game's mechanics, allowing her to lead her clan effectively and face high-level challenges.