Some Lemmings are good, because when the Teletubbies made them, they accidentally poured good essence into their system, thinking it was evil essence. The good Lemmings rebelled against the Teletubbies after they were given orders, so they were locked in a cell, but it was made of Styrofoam for some reason, so they all escaped. The other Lemmings now work for the Teletubbies.
The Lemmings are actually rather powerful, as they were made by the Teletubbies. They can shoot Energy Blasts, Blow Stuff Up, and they can control smells. They are not very smart, though, as if their leader makes a mistake, they can all end up getting harmed.