They may have a simple design and backstory but I think: an idea does not have to be complex to be great. Personally I think it is the coolest species in the Ben 10 universe.

 I called her like the main star of lyra constellation.

Biography:

Like other members of its species, Vega has almost absolute power, but because it is relatively young for its species (she is 200 thousand years old). Her power is not 100% developed and can not control it freely. Speaking in destructive capacity she can destroy whole galaxies with ease, but not an universe, she can manipulate reality, space and time but only to a certain extent. A mature specimen can create anything by just thinking about it, Vega must concentrate to do it. despite of not having its power developed to 100% it can survive practically everything, even the destruction of an universe. However, like the others of its specie, it has to follow rules that regulate the use of its powers, to preserve the universe and has multiple personalities that may interrupt its actions.