Poxium

Poxium Blight is tuned so that drawn-out fights matter more than a single heavy blow. Each successful hit applies the effect or raises its level, and the effect does not expire normally: its timer runs out and increments the level instead, so the stack keeps climbing up to level 15. The effect itself is harmless until it reaches level 10.

Its strength comes from escalation: each hit on a target with existing Blight raises the sword's damage by one, up to level 4, and the damage scaling caps there while the Blight effect continues stacking to level 15. Target Blight at level 4–5 deals 4–5 damage, and at Blight IV it deals 7–8 damage. Once the target reaches Blight X, the sword no longer increases damage and the heart reduction applies. Installed on a Fabric server for 1.20.1, Poxium works for both sides of the connection.