One of the most interesting mysteries that has been discovered in Red Dead Redemption 2 is the vampire roaming the city of Saint Denis. The city is a melting pot of different cultures, so it isn't all that surprising to learn that a vampire, known as the Saint Denis Vampire, has taken residence in the city, enjoying the local populace in every sense of the word.
You can also obtain a unique melee weapon by taking down the vampire (the Ornate Dagger), so you definitely need to get involved in this side-quest if you want to see everything the game has to offer.
There are no requirements to start searching for the hidden vampire. All you need to do is reach Saint Denis, which can be done at any time from Chapter 2 onward, and acquire the five Vampire Graffitis scattered all over the city. Once they have all been found, the vampire's location will be revealed, and you will have to fight it.
Vampire Graffiti 1
The first Vampire Graffiti in Saint Denis is found near the city's big Saloon. Reach the facility and then look for the red brick building to the south of the Saloon. The graffiti is found beside the entrance of the building, so it's easy to spot.
Vampire Graffiti 2
The second Vampire Graffiti in the city is found near the city's Gunsmith. Head slightly to the northeast of the shop to enter a courtyard with a tree. Locate the arches with metal doors nearby and proceed until you find an area with a chair and a few barrels. The graffiti is located right above the chair.
Vampire Graffiti 3
The third Vampire Graffiti can be reached by heading back to the Gunsmith and following an alley found right behind the shop. Proceed through the alley until you reach some doors. The graffiti is right in this area and it's hard to miss.
Vampire Graffiti 4
The fourth and second to last Vampire Graffiti in Saint Denis is found near the Trapper in the city's market area. Reach the Trapper and then head to the right of the marker until you reach an area with a few crates and barrels. Located the broken crate and look above it to find the Graffiti and the next clue.
Vampire Graffiti 5
The final Vampire Graffiti is quite easy to find. The writing can be found on the wall of the General Store in the city. More specifically, on a wall located in the southern part of the store.
Once you have found all the Vampire Graffiti, the location of the hidden vampire in Saint Denis will be marked on your map. As you likely already know, vampires are night creatures, and you will never encounter one in broad daylight.
So wait for night to come and then head to the specified location. Sometimes, the vampire may not be there as there are likely too many NPCs in the area. Just go away from the marked spot and then come back a few minutes later. If the NPCs have left, you will witness the Vampire eating a poor, unfortunate citizen of Saint Denis.
The fearsome creature doesn't like getting interrupted, so it will attack Arthur on sight. The fight against the Vampire can be difficult, as the monster can kill you with a single hit. To prevent it from getting close enough, activate Dead Eye and unload your weapon on the creature.
For you trouble, you can get a Batwing, Stringy Meat, and the unique Silver Knife weapon - you know, just in case you have to deal with any other vampires in your life. You never know...