Erosion

Erosion causes the maximum HP of a character or monster to drop for the rest of the fight when taking damage. Per example, a character with 1000/1000 HP that takes 200 damage will have 800/980 HP left. The amount of Erosion is 10% of the hp lost. This amount can be increased with buffs from spells, such as Pressure.
*Erosion is applied before taking into consideration linear reductions. It is actually possible to have hp eroded even if reductions block all the damage.
*Erosion no longer goes all the way down to 1 maximum HP. Previously, Erosion is capped at 50%.
*All spells that use maximum HP to calculate a value will use the eroded maximum HP rather than the "real" out of combat maximum HP.
*When the battle is finished, they keep their health percentage, which makes actually makes them gain HP because erosion is undone. Example. a character that has 1000 max HP and finishes a fight with 200/800 HP left will go back to 250/1000 hp.
Use Erosion for the following:
*Prevent monsters from healing back all their HP.
*Keep the power of monsters that do more damage at lower hp percentages down.