She is part of the royal guard, who specialises in doing overwatch for the castle and other royal areas during the night. She is specialised in stealth and operating at night, and is the leader of the night patrol.
She is a very serious and no-nonsense mare, is is frequently fed up with all of her troops attempts at entertaining themselves during the night shift (She isn’t a very fun mare X)). The only goof off she can tolerate (and actually has a friendship with) is Winter’s Night, who is the one thing keeping her away from popping a blood vessel X)
Also she also has a MASSIVE crush on Princess Luna and gets smitten and flustered everytime she is near her. Winter likes to tease the hell out of her for this XD