I could see that. I mean, with the darkness surrounding you, what's the fun in the deep sickness? (The Tumblr! post is exactly what I mean.)
So if we're equal opportunity characters, are we believing we're just humans in this mishap just pulled together? A police officer and a lawyer in an alien invasion? A fisherman and a pilot marooned on an island plagued by these sea beasts? Two mer-people controlled by the dark forces? Vampires who are trying to go the straight and narrow hounded by this looming darkness? There are endless possibilities.