Blood bats

Blood bats are giant carniverious bats that terrorize their victims at night. They are native to Haven, particularly Gallica and Ravil.

Description

Blood bats are giant nocturnal predators that distinguish themselves from other monsters by their primary food-source: blood. While they do eat meat, their primary source of nourishment is by drinking some of their prey's blood and letting them escape.

Blood bats are primarily active at night, and prefer to prey on herd animals such as sheep or cows, which they can drain a large amount of blood from without issue. They also hunt smaller animals such as rabbits, but they do not suck their blood but instead devour them whole. They are not very picky about their prey and will happily feed on humans.
They are primarily ambush-predators, but are no slouch in direct combat either.

Innate Magic

While seeming to be simply large beasts, blood bats actually use a lesser form of blood magic to more effectively drain their victims. It seems this is what they use to determine how much they can drain from a victim without killing them.

Hunting strategy

Blood bats are giant nocturnal predators. They will swoop down upon their prey in total darkness without any noise and either snatch them away or crush them to the ground and drain their blood. They seem to navigate their environment using their large ears and do not need any light. Due to their dark fur they can disappear into the night just as quickly as they appeared.

If you can find their den, you will be able to kill them in their sleep, making the fight a lot easier. Crippling a blood bat's ability to fly will also make the fight against them vastly easier. Still, even on the ground blood bats are very strong and decently fast.
The ideal weapon to fight a blood bat would be a long weapon such as a spear or polearm as well as ranged weapons, laced with poisons.
Loud noises will be able to dissuade blood bats and might even scare them off entirely.

Blood bats are territorial but only towards other airborne creatures. They are likely to attempt retreat if victory seems unfeasible and will fight ferociously if cornered. They will however fight to the death if they are defending their den or their young.

Trivia

It seems these creatures were one of the primary inspirations used by Ketior Fulgur in his creation of Vampires, who also use an innate form of blood magic.

Appearance:

Blood Bats are bats as large as a horse, with midnight-black fur and large ears.