Warlock - Pact of the Heart
Vanish Into Eternity, by Magali Villeneuve © Wizards of the Coast LLC
The Pact of the Heart is for warlocks whose patron reaches into their very essence — embedding a piece of the patron's power directly inside the warlock's body.
The Pact of the Heart rests on the notion of your patron's power burning - literally, burning — inside of you. Your basic pact boon gives you two abilities, both when you cast a spell: you can sacrifice some hit points to get twice as many temporary hit points, and you can take some damage to deal twice that much damage to one of the spell's targets. It's a roundabout but flexible way to burn your own health to punish your enemies.
It comes with a bunch of new invocations, too! Resilient Heart increases the temps you gain when you trigger your pact boon. Smoldering Flame lets you use the boon on cantrips, not just leveled spells. Vengeful Soul gives you advantage when retaliating against enemies - as long as you have temps up. Patron's Avatar lets you call on that embedded power to adopt a powerful guise. Armor of Pain lets you get unarmored defense, building for a tankier playstyle where you're using your temporary hit points to stand on the front line. Power Through Pain lets you burn hit points to recharge a spell slot. And Eldritch Fist lets you EB-punch!
And, as with my last pact, the Pact of the Heart is also fully compatible with the Omega Warlock, by SwEcky! It's a warlock revision that has been the standard at my table and many others for years, which rebalances the pacts and elevates them into full subclasses (for a dual-subclass design). The Omega version of the Pact of the Heart is similar, but with some key differences and reworks to better suit the situation. Searing Power provides the pact's base features. Armor of Pain comes online at 3rd, for a more opinionated playstyle. Wave of Agony is new at 5th, blasting nearby enemies with your patron's power when you cast spells. Vengeful Soul becomes a 9th-level feature, joined by Spreading Agony at 9th, for better range on Wave of Agony. Eldritch Heart is new at 18th, letting you pile a cantrip onto your Wave of Agony (keep in mind the Omega Warlock doesn't usually get Eldritch Blast).
As always, you're invited to come discuss and offer feedback on Discord!
