Mana Leech is a bonus featured on some items, the amount indicated is a percentage on every hit that the hit will steal mana from the target equal to 20% of the damage dealt rounded down (regardless of whether or not the enemy has any mana to drain). The leeched mana is shown as a blue number (as opposed to the red hp change value). A similar effect that simply drains the mana without granting any to the player is known as Mana Drain.