The Corruption is a dangerous supernatural catastrophe that occurs on Talos-II. Affected areas will exhibit various environmental distortions and anomalous physical phenomena.
Any other news about the story? I just hope that I don't need to play the main game to understand the lore.
Endfield is a standalone game, it occurs in the same universe but not same time/place as Arknights. It still borrows general aspects of the story like originum and originum infection though, judging by the originum crystals seen in the gameplay trailer.