Necrozma

Sun: Reminiscent of the Ultra Beasts, this life-form, apparently asleep underground, is thought to have come from another world in ancient times.

Moon: Light is apparently the source of its energy. It has an extraordinarily vicious disposition and is constantly firing off laser beams.

Ultra Sun: It looks somehow pained as it rages around in search of light, which serves as its energy. It’s apparently from another world.

Ultra Moon: Light is the source of its energy. If it isn’t devouring light, impurities build up in it and on it, and Necrozma darkens and stops moving.

Sword: It survives by absorbing light. After a long time spent slumbering underground, impurities accumulated within it, causing its body to darken.

Shield: It needs light to survive, and it goes on a rampage seeking it out. Its laser beams will cut anything to pieces.