Pollux Light allows Sui to control liquids, but although she primarily uses it on water, Sui can also manipulate other fluid substances like soft drinks and soup. She can also sense where people are through the use of liquids and can even use it as a means of extracting harmful substances like poison from other people's bodies. Sui uses it in conjunction with Souta's Castor Light to freeze and immobilize opponents.
Sui can also manipulate people's blood, which she demonstrated by slowing Nayuta's blood flow to the brain and killing a hostile parrot. However, a weakness of this ability comes from the fact she is unable to make liquids move very quickly, making her unfit for maneuver-based warfare.
After the timeskip, Sui has demonstrated greater control over her sigil, being able to use it unconsciously whilst her mind was preoccupied thinking about other things, as well as improving the speed at which she can move liquids, such as when she managed to stop Oboro from escaping and quickly trapped him inside a sphere of water.
- Sui and Souta's sigils are a reference to the famous twins of Greco-Roman mythology, Castor and Pollux.