First appearance: The Legend of Zelda (NES)
'Oh, this is easy' you may say. 'Oh, they're just bats with a silly name' To this I say YOU FOOL! Though appearing to be simple bats, they are in fact, I believe, demons. Or components thereof. let me explain.
Locale: Caves and Dungeons.
Keese are small and bat-like, with large, glowing eyes.
The Keese, in large groups, lie in wait for a hero to pass through; When they spot their prey they use team-tactics and erratic, unpredictable movements to kill their target.
The Keese are called into the world when dark power is on the rise, in order to feed off of the suffering and struggle.
Now you may ask 'hey where are you getting this from' to which I present the second part of this post.
First appearance: The Legend of Zelda (NES)
Now do you start to see where I'm going?
The Vire is large, demonic looking being composed of multiple keese.
Vires are stronger and cleverer than keese, and occasionally work as direct minions under a villain.
It is my belief that, rather than merely a magically created monster, Vire is a 'more whole' form of an ancient, nameless demon.
This demon suffered a defeat at some point in the distant past, and much like how the Vire can split into smaller Keese when defeated, the demon was scattered across time and space. If every vire and keese were to come together at last, the world would be doomed.