The Demon Tide doesn't just appear without reason.
More than two months into the apocalypse, humanity had already summarized the reasons for the emergence of the Demon Tide.
Abyssal Rifts scattered across the world spewed out countless Demonized Beasts every day; those beasts, like a virus, spread outwards chaotically.
The areas near the Abyssal Rifts had a higher density of Demonized Beasts, but in other regions, as the beasts roamed, their density would similarly continue to increase.
Once their numbers rose to a certain threshold, and if there were Sanctuaries with large human populations nearby, the scents would attract swarms of Demonized Beasts.
And that would form the Demon Tide.
This is why Awakeners needed to hunt Demonized Beasts from time to time, to reduce the density around the Sanctuaries, greatly decreasing the likelihood of a Demon Tide outbreak.
