While wearing and attuned to the cuirass, as an action you can activate it to summon three embers of archfire that surround you. Each ember provides a +1 to Armor Class and grants you resistance to fire damage. As an action, you can hurl and ember at a creature or object within 120ft of you. Make a ranged attack roll using your Dexterity modifier plus your proficiency bonus. On a hit, an ember deals 3d10 fire damage. Creature with resistance to fire damage take normal damage from an ember, while those without resistance or immunity to fire damage are treated as vulnerable to the attack, taking double damage. The ember remain for 4 hours or until you've hurled them all, and the bonuses to Armor Class and resistance to fire damage end when you've expended all the embers. You regain the ability to activate it at dawn.
Molten Wings
As an action, you can cause wings of molten fire to sprout from the back of the armor. Upon doing so, you gain a flying speed of 60ft for 1 minute. The wings trail flames behind you and any creature that enters the area or ends its turn in the flames takes 1d10 fire damage. You regain the ability to activate this at dawn.
Additionally, at the end of each of your turns while it is active, you can roll a d6. On a roll of 6, you can create a fiery fissure at a point you choose on the trail of flames. Flames burst forth in a 5ft wide, 30 ft long line from teh fissure. Each creature in the line must succeed on a DC17 Dexterity saving throw or take 3d10 fire damage and be knocked prone. On a successful save, the creature takes half as much damage and isn't knocked prone.
Plate consists of shaped, interlocking metal plates to cover the entire body. A suit of plate includes gauntlets, heavy leather boots, a visored helmet, and thick layers of padding underneath the armor. Buckles and straps distribute the weight over the body.
Notes: Resistance: Fire, Plate armor, Legendary, Requires Attunment, Str. 15 Required, Stealth Disadvantage