Boon of the Soul Drinker

Boon of the Soul Drinker
Feat
Prerequisite: Level 19

You gain the following benefits.
Grave Resistance.
You have Resistance to Cold damage and Necrotic damage.
Siphon Life.
When an enemy within 120 feet of you is reduced to 0 Hit Points, you can take a Reaction to regain 50 Hit Points. Once you use this benefit, you can't use it again until you finish a Short or Long Rest.

Source: Forgotten Realms: Heroes of Faerûn (FRHoF), page 43