[RPG] How to make a monster weaker

dnd-5emonsters

So I am DMing an open world campaign and my players are heading into this old ruins
infested with undead. So far so good, I made the map, random encounters, traps, monsters, treasure.

I have decided that I want the dungeon boss to be a vampire, since it fits the back story of the ruins. The problem is that a vampire is too powerful for the group: five 5th-level players. I thought about making it weaker, because it was starving for 500 years, but I don't know how to do that.

How can I make a monster weaker?

Best Answer

Start with vampire spawn stats instead of vampire. This has a CR of 5, so it's perfect as part of an encounter with your party if they're already low on resources from the traps, etc. Add in the shape change and Misty form traits from the vampire, which makes it harder to kill, but not harder to fight. Done.