Miasma’s Absorb increases your Health as you kill enemies as follows:
Health Points = Loadout Health * (1 + 0.004 * kills), rounded down
Note:
- As this is calculated on Loadout Health, perks that increase your Health Points (Max Health Up, Tank, GunHeart) do not have an impact. However, the Health Bonus from Mystery Crates temporarily enhance Loadout Health, so it probably does have an impact
- Because the calculation is rounded down, there is usually a fraction that is “lost” and the Health increment will be (0.4% of Loadout Health) rounded down. But eventually the “losses” accumulate enough to be counted and the Health increment on that kill will be (0.4% of Loadout Health) rounded up
- The effect is capped at 100%. As this requires 250 kills, you will normally only encounter the cap on endless events (haven’t tested if the cap is extended by Max Health Up / Tank / GunHeart) - unless you kill a ridiculous amount of spawn
Absorb also heals by the same amount as the increase (this is the number that gets displayed), which can be greater than the Health increment because of Healing bonuses (Dr. Toxic’s +10% at Level 20 and 50, +20% for each Combat Medic). See Health and Healing for details