When you cast a spell using your Pact of Blood feature, if that spell has additional effects for being cast at a higher level, you can choose to cast it at one level higher your warlock spell slots by expending two additional warlock hit dice, in addition to those spent to use your Pact of Blood feature. When you do this, in addition to the hit point loss from using Pact of Blood, you also take necrotic damage equal to a roll of the two additional warlock hit dice spent. #### Mystic Transfusion *Prerequisite: 5th level, Pact of Blood feature*
Instead of casting a spell, you can use your Pact of Blood to infuse another creature with a portion of your vitality. As an action, you can spend hit dice as you normally would when using Pact of Blood, plus an additional number of warlock hit dice of your choice, up to half your warlock level. Roll these extra hit dice. A single creature you are touching regains a number of hit points equal to half of the rolled result. When you do this, in addition to the hit point loss from using Pact of Blood, you also take necrotic damage equal to a roll of the additional warlock hit dice spent. #### Empowering Blood *Prerequisite: 7th level, Pact of Blood feature*
When you cast a spell using Pact of Blood, you can spend an additional warlock hit die in addition to the Pact's normal cost. When you do, you can roll that extra hit die and add it to the spell's damage total each time it deals damage to one or more creatures. This extra damage can't be inflicted on any one creature more than once per turn. #### Resilient Blood *Prerequisite: Pact of Blood feature*
When you lose hit points from using your Pact of Blood, you gain a number of temporary hit points equal to the hit points lost. Additionally, any necrotic damage you take due to the Blood Boil, Mystic Transfusion, or Vengeful Blood invocations is halved. #### Vengeful Blood *Prerequisite: 12th level, Pact of Blood feature*
When you use your Pact of Blood to cast a spell, you can expend an additional warlock hit die. If you do, you can roll the additional hit die and add the result to any spell attack rolls you make as part of that casting of the spell. You then take an amount of necrotic damage equal to the rolled result of the additional hit die.