Notes:

The Krsnik is a monster hunter from Croatian mythology who is eternal enemies with the vampiric Kudlak which spread plague and famine wherever they went.

When they encountered one another, they would don their fursonas and fight each other to the death.
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What?

It clearly states in the lore that upon encountering each other, they would transform into an animal, any animal, with the most common being dogs, pigs, oxen, horses or cats, and then fight each other.

The only way to distinguish which one is which is that the Krsnik will be pure white and the Kudlak will be pure black. In their human forms, they both appear as ordinary looking people; although the Kudlak will look a pit pale due to being an undead corpse.