Invocation: Shards of the Blood-Debt

When you cast Eldritch Blast, you can choose to infuse the beams with the lingering, toxic echoes of your former Hunter's Bane.

The Sacrifice: Before making the attack rolls, you can choose to take 1d6 necrotic damage, which cannot be reduced in any way.

The Benefit: If you do, each beam that hits a creature during that turn deals an additional 1d6 necrotic damage. The Bloodstone shard takes on a suspiciously claw like shape, the vapour trail a feline paw

Soul-Siphon: If a creature is reduced to 0 hit points by this attack, you regain a number of hit points equal to your Charisma modifier (minimum of 1) as Fistandantilus allows you to "glean" a portion of the life force he is collecting.