You’ve stumbled upon Thunderwatch, an island meant to be a production site for Ostia’s larger industrial collectives, eventually cancelled by Behemoths attacks.

Walking about the island, perhaps killing some Behemoths here and there, you find a crocodile-like Behemoth with glowing red eyes. This was the Nayzaga.

The Nayzaga doesn’t acknowledge you yet, only walking aimlessly before eventually seeing you.