Decay Addon

This is for Bedrock edition only.

This addon adds a new status effect (unofficially) called Blood Lust, causing the player's max health to deplete over time. If it reaches 0, you can't respawn, but you can kill things to get blood droplets and drink those to restore your lifeforce. The effect is inflicted by either taking damage from a sword called Bloodlust Vengeance, or drinking from a skull chalice filled with blood.

Lowkey go watch my video
It explains it better
www.youtube.com/watch?v=_HUCZAi6k_o&t=37s