Long before Whirring Cogs met Lavender Dreams, he had been a happy, single stallion at the Cloudsdale weather factory. Then a mad changeling queen destroyed his ideal world. (Prequel to "Change of Life")
Zevan was a loyal changeling and did his queen's bidding, although he questioned why she had broken the peace. After being badly injured though, he had to reconsider his future, and a unicorn mare with a broken horn was a surprising part of it.
Dandelion is Cogs' firstborn daughter, and a joy to him and his wife. As a changeling though, Cogs had no experience with raising pony foals, so when a crisis arises, he often has to wing it. Sometimes the solutions are more creative than others