Rianna is a Water Goddess who is all Power and Speed like her boyfriend R.O.B and has a unique rivalry with Kelly.
Rianna is one of the victims of a murder spree in grim Purpleverse game Mario Mysteries. As she is a water goddess, the killer forces her into extreme heat, thus evaporating her water powers. He then knocks her out, plants bombs around her, and escapes. Despite Daisy's est efforts, the bombs go off, killing Rianna.