I will post background information in the comments, but they're Genderless

Necrozma, known as the Prism Pokémon, is a legendary Psychic/Dragon type Pokémon. Its mysterious and enigmatic nature has captivated trainers and researchers alike. To understand Necrozma's backstory, we must delve into its origins and the legends surrounding this extraordinary Pokémon.

According to ancient tales, Necrozma was once a radiant being that possessed an immense light energy. It resided in a realm known as Ultra Space, a dimension parallel to our own. Necrozma's luminous brilliance was said to be the source of light for Ultra Space, illuminating its inhabitants and providing life-giving energy.

However, something went awry in Necrozma's existence. As the tales go, Necrozma encountered another powerful entity known as Solgaleo or Lunala, depending on the version of the story. These two Pokémon clashed, and in the ensuing battle, a portion of Necrozma's light energy was stolen, leaving it weakened and in a state of perpetual darkness.

The loss of its light had a profound impact on Necrozma's psyche. It became consumed by a desire to reclaim its stolen energy and restore its former glory. In its relentless pursuit, Necrozma traveled to the Alola region, where Solgaleo and Lunala resided. It was here that Necrozma's true power was unleashed.

When Necrozma arrived in Alola, it discovered the presence of Z-Crystals, a powerful energy source capable of augmenting Pokémon abilities. Necrozma was drawn to these crystals, recognizing their potential to replenish its stolen light. It is said that Necrozma's desire for the Z-Crystals led to its ability to merge with Solgaleo or Lunala, resulting in the birth of two new forms: Dusk Mane Necrozma and Dawn Wings Necrozma.

With these new forms, Necrozma became even more formidable, harnessing the power of both light and darkness. Its relentless pursuit of the stolen light energy and its encounters with trainers in Alola became the stuff of legend. Trainers who faced Necrozma in battle were awestruck by its sheer power and the overwhelming presence it exuded.

Idk, too lazy to come up with an original backstory

I knwo who is this pokemon they are on of my fav

Oh cool