Saint Denis Vampire

The Saint Denis Vampire is a character found in Red Dead Redemption 2 as part of a side-quest, although not necessary for completion of the game's main story the quest provides more insight into the world and also acts as a sort of "easter egg" in the game by providing the chance to hunt down a vampire, though it is unknown if this individual is a true vampire or simply a mentally ill serial-killer.

History
The Saint Denis Vampire is an unnamed killer who stalks the streets of Saint Denis, leaving behind strange messages on varied walls - this ultimately leads the player to a confrontation with the vampire in an alley, where he is feeding on a recently killed victim.

If antagonized sufficiently the vampire will proceed to attack the player and try to kill them with his ornate dagger - regardless of whether antagonized or not the vampire will happily warn the player of his great age and power, fully convinced of his superiority as a creature of the night.

Abilities
the vampire shows no supernatural abilities but is armed with an ornate dagger, which he can use to attack and stab at victims or potential threats - he also has long, almost claw-like fingernails but does not seem capable of using them in battle.

Trivia

 * his appearance is based on Nosferatu but when exposed to sunlight he does not burn, this suggests that he is not a true vampire but rather a deformed and mentally ill criminal.