How do Vampyres work?

Vampyres can drain players and living entities of blood, replenishing their own pool of blood if not full. "Living" for this effect should only inlcude farm animals and villagers/pillagers/witches by default, but be modifiable through taglists and datapacks to include or exclude specific entities as desired.

Only the intelligent creatures such as villagers/pillagers/witches will have a blood meter of their own, other valid targets will simply take damage each time they are fed on by the vampyre. This too will be controllable through datapacks.

Damage will be dealt to all entities that are fed on by default unless asleep, and this property should be togglable via config files. If the damage is configured to be less than zero, this feature is disabled.

Draining too much blood will also cause the entity to take damage, with the amount needed drained and the damage being dealt again configurable through the config files. Setting the damage to less than zero disables this feature.

Vampyres should also have an accelerating feeding effect by default, causing the rate at which they drain to increase after each blood unit taken until a timed interval passes. How many increments, how quickly each speed is reached and lost, and what speed each increment feeds at should probably be configurable through a datapack asset file.

Unlike feeding on food items, vampyres should not be "stopped" when the meter is full, the units of blood consumed are just wasted.

Blood given to the feeding vampyre does not scale with the blood taken, and by default should restore an amount determined by what is being fed upon, with intelligent creatures like villagers/pillagers/witches restoring more than livestock, and with an added bonus for each level a villager has and their reputation with the vampyre.

Damage taken from feeding may have to be it’s own damage type for mod and update compatibility purposes. The resource shouldn’t be referred to as blood in gameplay as to align with Mojang’s own no blood references policy and better fit into the vanilla experience.

Feeding upon the living is the staple feature of a vampire that sets it apart from most other undead, spirits, and demons; there’s simply no way this could be adapted without the quintessential property that makes a vampire a vampire.

But even just for themeatic purposes these vampyres are intended to be hunger and obsesion incarnate, and making this feature is an extension of that theme. This is also why the feeding accelerates by default; it lets me both build that theme further and adapt the "vampire cannot stop themselves once they start" trope.

Further building onto the relentless hunger themeing, it then also makes sense that you can drink regardless of the status of your blood meter, risking waste if not properly managed.

The enhanced feeding on sleeping targets at night is partly to help build that folklore-y vibe and partly to help out less technically inclined players who may not want to go through the effort of caging up villagers in trading posts. It works as a vampire trope for good reason.

Vampyres should not be able to gain hunger or saturation from any source other than their internal blood meter.

Restoring lost hunger should occur when the vampyre sleeps in their coffin, with each hunger point roughly restoring at the same rate air bubbles would be lost when a living creature is underwater. Blood is consumed in order to restore each point of hunger, with the amounts configurable through the mod config files.

Upon wake, the vampyre’s blood meter is reset to empty by default, and this can be disabled through the config files.

This is another half of the core element of vampirism; they must feed upon the living to sate themselves. However, splitting the restoring from the feeding itself can allow for some more tropes to be adapted, like the need to return to their grave each night.

We again build on the appetite theme by having all blood be consumed on rest, meaning a vampire player is encouraged to feed each night or else stay awake through the day and risk being stuck without a safe way of returning home, potentially succumbing to hunger, or be caught without a way to properly heal.