|That is not the intended use for my confetti cannons….|
|—River Styxx in "Haunted"|
River Styxx is a 2014-introduced and all-around character, as well as a grim reaper, or rather a Reaper In Training (R.I.P). She is the daughter of the Grim Reaper, and attends Haunted High, a school for ghosts. Being the daughter of the Grim Reaper and niece of Charon, her monster heritage and her history are a mixture of a ghost and a skeleton (Or her heritage is mixed with ghosts and skeletons). Being a grim reaper: River more or sort of has two main monster breeds or monster races; a skeleton and a ghost, while her main basis race is a grim reaper, so to speak. She is most likely more ghost than skeleton, however. Due to her grim reaper lineage, she is actually neither a hybrid, nor a ghost, nor a skeleton, but more as a strange mixture borderline of ghost and skeleton, as well as grim reaper.
River Styxx is voiced in English by Ashley Peterson.
Unlike the traditional version of the Grim Reaper, River is extremely cheery, upbeat and bubbly, and loves bright colors and candy. She has a lot of energy and finds it hard to concentrate and stand still. Although, she does get evil feelings to scare other monsters.
She loves to make people laugh and smile, and is always telling stories, planning parties and fun events for others, particularly the spirits she and her father transport to the Ghost World.
River is a Reaper In Training, (R.I.P) which means she is only allowed to carry a staff around instead of a scythe. Due to her Grimm Reaper heritage, and she will one day be able to perform reaper's work, and pursuit all powers a reaper should have. Despite being a skeleton AND a ghost, she is however NOT a hybrid, but more as a "mixed borderline species".
River has purple skin, which is transparent on her lower limbs so that her bones are visible. Her hair is blue, pink and purple. She has ghostly big blue eyes and, because she has both ghost and skeleton traits, visible lines on her mouth, to represent teeth, visible eye orbits and skeleton nose.
River is a Reaper in Training, meaning that most of her reaper powers haven't been acquired yet, although, she does have several powers both from her ghost heritage and from her further reaper background.
- Floating: Due to being a ghost, River is able to float around, as do the lightest parts of whatever she's wearing and her hair.
- Permeation: She is also able to phase through solid material, or in other words, use permeation.
- Astralkinesis: River also carries a mysterious aura around her, and owns the ability to change the environment around her, like the sky and the water, and usually uses to set the atmospheres for her ghost stories and scare the new ghosts who come along to her boat.
- Voice Manipulation: River can alter the pitch of her voice.
- Story Telling: River's a talented story teller, especially if it involves ghosts.
- Sailing: Due to her harbor-like life, the way she was raised around boats and due to having a popular sailor as a father, River has the skills of a well-rounded sailor and is savvy enough to where she is allowed to be in charge of the Grim Reaper's boat by herself.
River's father is the Grim Reaper, one of many responsible for transporting passed on ghosts and spirits to the Ghost World, and one of who, unlike the original-known-based Death of Personification, or what the Grim Reaper was originally known out to be; her father is not only an undead skeleton, as her father is also a ghost. He has a hard time dealing with his daughter, who is not what a reaper is expected to be. As a result, he might be a little strict on her.
In her diary, she mentions her father has a cousin, a former reaper who broke the rules and was punished by being banished to the real world, and now works as a high school guidance counselor. It's highly implied this cousin is Mr. D'eath. River's uncle is Charon, the ferryman of the dead in Greek mythology.
River has a skeleton raven, Cawtion. Her pet's name is a pun mixture of play on words of the words: "caw", as a sound a bird makes, and the word "caution".
- January 22, 2014: Mattel requests the trademark for River Styxx.
- April 09, 2014: Mattel requests the trademark for River.
- July 26, 2014: River Styxx's debut doll is on display at San Diego Comic-Con International.
- March 25, 2015: River Styxx makes her 3D cartoon debut in "Haunted".
- Her name comes from the river Styx, the river which separates the realms of the living and of the dead in Ancient Greek mythology.