I wanna be the Hero, but I’m the villain

In this place a being called Diamonds exist and love to keep the balance of the universe. They kept this balance for millions to billions of years, yet all was destroyed due to the Black Diamond if Chaos' feud between the Golden Diamond of all elements. The war caused most of the Diamond race to diminish. And the rest ran away in fear for their lives. The White and Purple Diamond were used to destroy the Diamond world and died. Who would have known after the Diamond world, a child would be born with a half Black and Purple Diamond on her chest. Her name was Iris. 

She is seen to be an ordinary child with no special powers at all and lives in a heroes era. However her past is much different. She was a princess of another planet that went on a rebellion and Iris and her two sisters were separated by a space time travelling machine. Iris ended up on earth and was adopted by a couple. Her two sisters' part would be mentioned in another story.

She lived In a world of People called Ability Users who had the power to become heroes and Villains.  Iris always wanted to become a hero when she was a child and forgot about her horrid past.

AS the inheritor of the Black Diamond Gem would she be a hero or a villain.