Tina

Tina is a bear who lived in the Backyardigans and Frontyardigans' neighborhood and is Kevin's twin sister. Like her brother, she is always nice to the gang in real life. But she always pretends to be a villain no matter which episode she appears in.

Also, like Kevin, due to episodes not needing a villain, and episodes that have other characters playing more superior villains, Tina doesn't appear very often.