Some(そめ) + Tsuki(つき) = lit."With Dye/color"
Unknown, probably adolescent
Sometsuki (そめつき) is the main character of Ultra Violet.
Like most of the characters in Yume Nikki fangames, Sometsuki refuses to go out of her room when awake, only opening her door when she is asleep.
Sometsuki has long, dark, black or pale dark violet hair, dark violet eyes, a white short-sleeved shirt with a violet ribbon/bow at the collar and a black long-sleeved shirt underneath, and a matching violet/violet checkered skirt. She also has dark plum shoes, and is known to be one of the few Dreamers with open eyes, similar to Poniko from Yume Nikki.
Sometsuki can be depicted as cold and stoic due to her eyes, but most people interpret her as a girl who loves cute things (especially rabbits), and enjoys most parts of her dream world. It should also be noted that on the menu Sometsuki's Title is "Sleepwalker".
It has not been shown why Sometsuki refuses to leave her room, nor is it clear since most of her dreams are rather peaceful, but this could be because she does not want to remember the events that caused her to become a shut in. There have been however, a few unsettling worlds/places, that stand out since most of the game is rather soft and relaxing.