What's up with Necrozma?

Question

What I was kinda wondering about Necrozma is that we know that it forcefully took control over Lunala/Solgaleo in the games story to absorb their light out of anger and pain.

So what is the relatioship they have after you have fused them together again, is it like a symbiotic relationship between the two legends where one grants light to sustain itself and other grants other powers?

Comments

https://bulbapedia.bulbagarden.net/wiki/Cosmic_duo This article will probably have the answer after it's been updated.

Answer 1

What is Necrozma's Core? Iwano: I dug deep into the original setting in my own mind, reconstructed it, and gave Necrozma, Solgaleo, and Lunala, this deep relationship. Necrozma can control light but it cannot create light. So its has a strong desire to steal the light Solgaleo and Lunala, which both possess their own light. These three are always struggling agnaist one another in Ultra Space. Necrozma might steal the night of the others and flee, then solgaleo and Lunala might give chase and take the light back-and on and on it would go. They always lived that, but the balance of this relationship among them but was thrown off due to the interference of the Ultra Reacon Squad. In Necorzma's World and the people living in Alola, like the protagonist. As a result- even though really only ever needed small amount of energy-Necorzma comes to gain a huge amount of engird beyond what Necrozma anticipated, when it captures Solgaleo or Lunala. And because of the gaining of this excessive energy, Necorzma goes berserk. This is what we called "Ultra Necrozma". We wanted to depict the drama of the hero encountering this Ultra Necrozma at the climax of this story. It was the actions go the people that made Necorzma run amok, but in the end, it will be caught by the player and join them as a ally. Thanks to that Necorzma will be able to draw forth its won true power again and become able to accompany the player on their island challenge, without needing to target the lives of Solgaleo or Lunala. We wanted to illustrate how the relationship between Necorzma, Solgaleo, and Lunala, whivh had been destroyed by the past, is forged again by the hero's actions and the balance of the world is restored.

source
Sorry about the typos. The person who transcribed this interview onto Bulbapedia was apparently very sloppy.