>>51439900By the third legendary being a giant crystal that deflect lights to all its colors as he choices, aka teracrystal.
I'm not sure how it will play in the past and future thing but the legendaries looked at the sun, scarlet is meant to represent the last because of the colors of the dawn, while violet is the future cause it's those of the sunset.
In theory light being reflected created the paradox pokemon. Also the professors have the sun's phases on their blackboard
Apart from the past and future thing, the theme seems extremely similar to gen 7, the third legendary is a star yet again, like necrozma, which also was made of crystal, light branches in all its colors since it's even a prism, hence the z crystals with all the types. The team is even called team star. It's gen 7 but there's the past and future theming into it too