Yoko Ritona was an extremely skilled sniper, and a long time member of Blue Team. She was one of the most popular members of Blue Team, having joined them during the War of Pawns, and remaining on far beyond into the Rise of Chaos. Yoko was an exuberant, fearless young woman with a shapely and athletic body. Yoko was listed as the UNSC's #1 marksman in the galaxy, and her skills in long-range warfare are unmatched by any human.
Ever since the Mythic Dawn Crisis, Yoko displayed a strong sense of caring and passion for David "Solid Snake" Thatcher. On multiple occasions they both showed their caring for each other's safety, and they often embraced each other affectionately. Despite their age difference, it has been shown that Yoko and David were indeed in love, and at the time of their disappearance after the Rise of Chaos, they produced two children together, Ryuko and Zeronus.