How do seaborn tie into the larger story of Arknights anyway?
Seaborns are implied to be Cthulhu counterpart in Terra and originates from *something* in the depths of the ocean. Said thing reproduces using human/animal corpses as medium, spreads like fungis on crack and might be more dangerous than Originium infection because they're sentient and began to wake up, trying to take the surface world.
Huh, and here I thought AK's story was mostly a political one with a war backdrop.
There are something like 4-5 potentially apocalypse-level events as well as a bunch of lesser events, and part of the politics is trying to manage several nations responses or preventing factions from taking advantage of each other in the chaos.