There's at least three sets of Shadow Twins. They all have nearly identical powers and use the same team names. There's Lucy and Colin Palmer, who are pictured above. There's Nikki and Steven Lopez who were last seen in Chapter 4 of Book 1. And there's Paul and Emily Rossi, who StarPower never fought because they lived in Washington State and are also heroes. 

Each of these pairs are fraternal twins, and all of them have the power to manipulate shadows and make them physical. Unfortunately they also have the drawback where only one of them can be a person at a time. The other twin has to remain the human twin's shadow. It really sucks. But they've all made it work.

But just think about it. No privacy.