Rio's feet and legs are covered in sleek black carapace segments, with a ragged white skirt worn around her human waist. She wears a torn white shawl around her shoulders, with her breasts having hardened carapace segments cradling them. Her arms shift into monstrous pincers below her elbows, while behind she has a large black scorpion tail with a long stinger. She has messy brunette hair that goes down to her shoulders and appear unevenly cut, and her eyes are golden colored.
Rio is at her core a murderous monster who relishes in torturing others and the screams of her victims. Despite often having a stoic expression and a dull, almost bored sometimes, way of speaking, Rio is as cold and devilish as the rest from The Sisterhood are. She butchered a group of human women and children during one of their raids, with the remains of their corpses either being hacked into pieces or bearing frozen expressions of agony on them. According to her, torturing others is almost as pleasurable as sex itself is for scorpias.
Her stinger has a venom that, instead of poisoning or killing her prey, acts as a powerful aphrodisiac. The venom works on both men and women, which causes them to become extremely aroused and dulls the rest of their senses in the process. Even so, Rio has shown firsthand that the stinger can also be used as a lethal weapon with its piercing power.
Being a scorpia she's incredibly speedy and agile, able to dash about in any direction at a moment's notice, and even up walls, while also being physically strong in comparison to typical human fighters.
Rio is first seen in Act X when she confronts Mae, Milly, and Mika Harollson alongside The Sisterhood in Nibelvale. Learning that the sisters are monster hunters, Rio challenges Mika to a fight in order to be the one to torture her to death. During their fight Rio and Mika come to a stalemate, with Mika, using her sword skills and magical attacks, being unable to harm the speedy scorpia while narrowly avoiding her attacks in return. Even after a powerful wavebeam strike hits her foe dead-on, Mika is unsuccessful in harming the resilient monster. Before they can progress into another duel, Rio quickly bypasses Mika and fatally plunges her stinger through Mae's neck, killing her almost immediately, all because she wanted to cause Mika more pain. During this moment Rio's emotionless masks slips, offering a brief view of a very malicious smile that expressed her true nature. Mika tries to retaliate with a magical spell, however a counter-spell enchantment is erected in the area, belonging to a witch named Alice. Milly tries to kill her, only to be bound by the witch's magic. Mika attempts to slay the witch, only for Rio to inject her venom into her, causing the human to become overwhelmed in pleasure and unable to think straight, so much that she doesn't fully grasp the sight of Milly being fatally slammed into the ground by Alice, or Rio using her stinger to puncture Mika's right eye. Her mind is brought back to its senses after Mae's repeater malfunctions and shoots Alice's focuser with a lucky shot, breaking the counter-spell enchantment and snapping her back to reality from hearing Alice's screaming. Before Rio can strike her down, Mika unleashes her Maelstrom spell, annihilating Nibelvale and most of the grunts of The Sisterhood. Rio and Alice survive and prepare to finish off a weakened Mika afterwards, with the two then fleeing from Daemon Warrick and his followers arriving on the scene.