Chain Healing

Blood Injection and Blood Shot grant you 1 stack of Chain Healing for 4 seconds. Each stack of this effect increases mana consumption and healing effectiveness for these spells by 25%, and blood consumption by 1, and reduces their cast time by 1 second. Stacks up to 4 times.
As soon as 4 stacks are gained or after the effect fades, both spells' cooldown will be 21 seconds.