These two cuties are Nimbus Bellows and Lofty Leap, children of Bulk Biceps and Fluttershy.
Nimbus Bellows — Nimbus is Fluttershy and Bulk's son and the older child. Despite his intimidating size for most colts of his age, he is, like his mother, very shy and reserved. He is also calmly spoken and slow to anger. He shares his grandfather's love of clouds and enjoys spending his days watching, studying, and collecting them. In fact, his favorite activity is watching thunderstorms and gazing at the various cloud formations, something that baffles his younger sister, who is deathly afraid of them. Because of his weight, he is not a very fast flyer, but enjoys being high in the sky. Fluttershy tends to spoil him, making him a bit of a mama's boy.
Lofty Leap — Lofty is Fluttershy and Bulk's daughter and the younger child. Known for being loud and boisterous, much like her father, she is the most hyper and excitable of the two children, and loves to play, twirl, and run around often. Like her dad, she is also very athletic and competitive, showing talent in both dancing and gymnastics. She has a particular love for ballet, and attends a class in town regularly. Despite being her complete opposite, she has a deep admiration for her older brother, and often runs to him for comfort whenever she is afraid of something. He, in turn, likes to share facts about things he knows to help her feel less afraid. She always loves to wear her pink tutu, which was made for her by Rarity.