The Storm can refer to two separate subjects:
Save The WorldThe Storm can refers to the purple storm that wiped out 98% of the world's population at the beginning of Save The World's story. It creates monsters and has taken over Earth in Save The World. It is unknown why or how it formed in the first place, but it seems to be hostile to any creature other than Husks, killing any creature that ventures inside.
In Battle Royale, the storm is used as a barrier to keep players in the playable area and it will shrink until it is entirely closed in, dealing damage to players' health outside the storm circle's perimeter. Any shield is ignored. The storm's visuals will intensify and appear more deadly as the match goes on.
The storm can move during phases 5, 6, 7, 8, and 9 (in competitive only).
The below details the changing Storm in Battle Royale:
|Stage||Grace Period (minutes)||Shrink Time (minutes)||Damage while shrinking||Damage after shrinking|
The origins of the Storm are not clearly stated, but it appears to be an interdimensional force literally made from pure Evil. Its runes are shared by not just The Cube but by many sinister objects and beings that do not seem to be related to it. This implies that the runes are simply a universal symbol of Evil, and that the Storm and Cube are physical manifestations of it.
The Storm apparently entered the STW universe through the dark Rifts (different from Battle Royale rifts) that spawn randomly in various zones. This likely means that it comes from its own dimension of darkness, and entered both the BR and STW universes through these rifts.
The Storm is able to produce evil clones of humans and probably other life forms as well. This is shown in STW where it creates the Husks based off of a number of normal human beings (No, the husks are not infected humans. The developers themselves said this.).
In Battle Royale, the Cube was first assumed to be a creation of the Storm in Season 5 which made dark clones with the first being Brite Bomber, followed by Jonesy, Wild Card, Red Knight, Tricera Ops, and Rex. A second creation was formed in Season 9 when Tempest was born. In Chapter 2: Season 2 the Cyclo skin was released into the item shop. The Cyclo skin is believed to be another creation of the Storm.
During The Device Event, the Storm was drastically changed, replaced by an ocean-like wall. It is possible that that is what flooded the island.