Raiment of the Final Dawn (Patreon)

Wondrous item, legendary (requires attunement)

Radiant as the sun, pure as the sky, strong as the earth. While wearing this coat you have advantage against being charmed or frightened and you can understand and speak Celestial. This item can store up to 3 charges. When a creature is reduced to 0 hit points within 30 feet of you, it gains a charge. If the creature was an undead or fiend this item gains 2 charges instead.

Consecration. From the blood of the infernal that stains this holy vestment, light shines forth. You can use a bonus action to activate this feature, causing you to become a holy avatar of battle. While this feature is active, at the start of each of your turns you regain an amount of hit points equal to 1+ your constitution bonus, you have resistance to fire and necrotic damage, and melee attacks you make deal an additional 2d4 radiant damage. At the end of each of your turns, the raiment loses a charge until it has no charges remaining, at which point this feature is no longer active. You can use this feature a number of times equal to half your proficiency bonus rounded up, and you regain all expended uses at the next dawn.

Corruption. If a creature is reduced to 0 hit points within 30 feet of you while this item has 3 charges, at the start of your next turn you must succeed on a DC 18 Wisdom saving throw. On a failed save you move directly towards the nearest creature to you and use the attack action against that creature. If there is more than one possible target, roll to randomly determine the target. You then regain control for the remainder of your turn. If you are under an effect that prevents you from concentrating (such as the barbarian’s Rage feature), you automatically fail this saving throw.

It was a fierce and terrible battle that none may ever forget. For hours, days, weeks we soldiered onwards. With each passing minute we could feel our resolve crumbling against the endless wave of monsters that sought to tear us to shreds. But then, we saw them; standing amidst the blood and smoke, wrapped in garb as beautiful and as bright as the dawn. With holy light and furious steel they cleaved through the fields of demons, filling us with hope when all seemed lost. Yet the most surprising thing of all was that, though I could have sworn the battle had dyed them crimson from head to toe, at the end they were as bright and pristine as when they had first arrived.

Journal entry of an unnamed soldier from the 61st crusade.