Vriska is, more often than not, a huge bitch. She gets easily bored, makes shady deals with people, does horrible things to her "boring" friends, and then slams herself because nobody likes her or - even worse - hates her enough.
Vriska is arguably the most powerful of the 12 trolls and enjoys showing it off, with her ability to predict the future (using her vision eightfold and magic cue-ball) steal others luck (using her god tier abilities), her ability to mind control others, and call upon her ancestors power (through rolling all 8s on the Fleurette octet) she is a force to be reckoned with.
In some cases when one of her magic cue balls explodes, she will have a robotic arm and eyepatch glsses...