Ralts♀

Ralts♀ is a Psychic-type Pokemon with high potential. She is stern and quiet, and cannot communicate verbally with the user or anyone else except Pokemon. She is diligent and extremely demanding, and is also kind and somewhat cynical with those with whom she has no social bond. She is extremely proud, but knows how to behave.

Ralts♀ being a pokemon has 3 evolutions, all of Psychic type, one more powerful than the previous, everything starts with its weakest state, "ralts", then its power increases to a new transformation, "Kirlia", and then to "gardevoir" the pinnacle of its species potential.
In order to evolve, they must overexert themselves mentally and physically. They normally do this when they want to defend something and their current power is of no use to them, and that's how they evolve.

It uses the "modern" world of Pokemon along with its history and traditions, and obviously the other Pokemons.