The remaining member of the family of Leafhelm my OC and pen and paper rpg character is his older sister Whistlewing. Unlike her mapmaking brother she stuck with the military tradition of the family by joining the E. U. P. Guard and the Protective Pony Platoons, the organizations which preceded the later Wonderbolts (according to the Episode “Testing Testing 1, 2, 3”, S4E21).  
She is a very assertive pony and may have a somewhat intimidating effect on others, but she is also a perfect example of a character with a tough skin hiding a golden heart. For example, when our pen and paper rpg group met her for the first time Leafhelm told the others that her barking “Speak louder!” at anypony was like a great compliment showing that she liked whoever was told to speak louder while she would tell anypony she didn’t like to be quiet.  
Part of her noisy attitude may come from an affliction she was born with. Her left wing is a little crooked and while that doesn’t affect her flying (she is an excellent flyer) she will always produce a whistling noise when flying, especially at high speeds.  
In this particular sketch she is looking sad and angry based on the scene in our rpg when the other characters from our group told her about the presumed death of her brother (whom she loves very much and vice versa, in spite of their different nature). The sketch comes with one of my most persistent drawing flaws namely the head being too small compared to the rest of the body / the neck being rather long (I try to draw close to the proportions of the MLP series). Recently I vectorized this drawing and hope that the proportions work out better there. I’m going to upload the vector version right away.