Data Packs

Vampirism uses data packs for vanilla related content as well as for some custom content. This allows users and content creators to further customized their Vampirism experience or even built new challenges.
Have a look at the mod data directory main and generated. Or at the incomplete and outdated example repository here

How it works

Checkout the Minecraft Wiki to see how datapacks work.
Installing them
Creating them

Also make sure you are familiar with the namespace concept. If you want to modify/override Vampirism's own definition you have to use vampirism for everything else use your own.

Things that are customizable

Besides the already mentioned vanilla contents you can also customize:

• Player Skill Trees
• Blood Values
• Alchemical Cauldron Recipes
• Weapon Table Recipes