Ryuko is a member of the Second Team, a female human fighter who is the daughter of David "Solid Snake" Thatcher and Yoko Ritona. After Chaos' defeat in the 2160s, when the original Blue Team were taken into Aetherius, she was born for the purpose of inheriting the mantle with the rest of Blue Team's offspring. She is a member of the Second Team, with the role of a skilled swordswoman. She is the sister of Zero.
Ryuko is medium-height, athletically-built and shapely, like her mother. She has bright blue eyes, and jet black hair with red streaks. She bears a strong resemblance to her mother, whereas her brother Zeronus is said to more resemble their father.
Ryuko is often seen wearing a casual black shirt and skirt, but in battle she utilizes an experimental cybernetic body armor named Senketsu, which she stole from Cerberus' East Asia Division. Also from this raid she acquired her deadly weapon, the Scissor-Blade, also Cerberus tech, which she wields with deadly precision and power. She is a very skilled sword-wielder, and is considered to be one of the most fearsome warriors ever to fight for good.