From Path of the Vampire Wiki
Paladins are, simply put, individuals who have been imbued with power in the same way one would enchant a sword or a relic. Their power, it is thought, comes from a mixture of the natural life force energies which have been instilled in their runic tattoos, and partly from the fae themselves (or a single fae, or perhaps spirits of dead demifae).
Legend says that King Arthur (539 C.E.) was the first paladin, but this cannot be substantiated.
The first verified paladins were said to be a group of knights from The Order of Saint James of the Sword who were formed in 1170 C.E., though it is unknown how they came to meet the sorcerers who joined their group and imbued the first of them with faeish tattoo runes.
'The Paladin takes you to a hideout, where she instructs other hunters to perform a strange ritual on you. They tattoo mysterious runes and symbols onto your skin, then they spend hours meditating over you. Your runes begin to feel increasingly hot, and eventually the searing pain is almost unbearable. Suddenly, the pain stops.
When you are done, the Paladin explains how to use your newfound strength and skills. You feel superhuman! '
A Paladin can only be tattooed and enchanted by a sorcerer. Though other individuals can enchant objects, it is only sorcerers who have the abilities needed to perform the same process on a living being.
As with blood thieves, many paladins die in the process of being initiated. The pain of having runes burned into their skin is made intensely greater by the raw energy that is needed to infuse the runes.
All paladins have tattoos, but only some have very obvious faeish runes. Some paladins have their faeish runes masked with surrounding patterns, images, or interlocking symbols around them.
Relationship with the Fae
Paladins have no direct relationship with the fae. Though their tattoos are partly faeish, and without those faeish runes they do not have their paladin powers at all (though they would be superhuman for a limited time), it is impossible to say if the fae (or a fae) is directly responsible for gifting all paladins with their unique powers, or if the runes tie them to a specific type of invisible / spiritual demifae in the same way that rituals are able to command demifae to perform certain tasks.