The Harfle is a forest monster and is referred to by it/its pronouns

This is a creature voice. 

An 800 ton, serpent-like ancient tunnel beast. Everyone knows and fears the Harfle. You’d have to be insane to enter its territory on top of that plateau. Usually. It spends most of its time underground and dormant, but it is able to feel the vibrations of anything that walks into the area. When it’s above ground, it will launch itself into the sky to catch anything that flies by. As barbaric as it sounds, The Harfle isn’t a mindless brute. If anyone ever lived long enough to communicate with it, they’d find that The Harfle has an extremely intelligent understanding of the world, beyond what any human mind could comprehend. Its roar is like a terrible, anguished, and weirdly human scream.