Muriel is the main character of the Watercolour series. Muriel is the commander of colour across the world, and laid dormant inside a clam shell for a million years. Muriel's legend and ability to control colour are the reason Neptune took away the worlds colours, as her legend states she will return once a millennia to keep check on the colour spectrum. She wields a magical paintbrush.
Muriel has a sea foam coloured skin tone, wears a coral coloured tank top, and short olive green shorts. She has brown leather leg straps wrapping around her thighs and a matching brown belt with a golden circular buckle. Her hair is tied up in a high ponytail. Her hair is colourful, with streaks of teal, blue, green, pink, and yellow. Her hair is adorned with various ocean creatures and shells, as well as multiple coloured pearls. Her shoes are an algae shade of green and appear to grow up her legs, on her shoes are various blue and pink pearls. Her shoes give her the ability to walk on both land and sea.
- The name "Muriel" was chosen for 3 reasons;
- The name itself is a Gaelic name that means "bright sea", relating to Muriel's aquatic abilities.
- Muriel is Cassadony's maternal grandmothers name.
- Muriel is a name similar to the world "Mural", a type of painting painted directly onto a wall, linking to her painting and colour abilities.