Stars, from recent angels

Hi all!

About Angels who have appeared for several months : In the star menu (NOT evolve menu) we can add a number of stars up to 5.

I would like to know if by increasing the number of stars, we just increase the power and statistics of the angel when it is used as the main angel...Or if this angel is assigned to one of the characters on the team does it also increase the statistics of this character.

Thanks for replies...