[WIP] Valestryx, Embodiment of Flame

Legendary Resistance (5/Day). If Valestryx fails a saving throw, he can choose to succeed instead.

Superheated Scales. Any creature within 100ft of Valestryx experiences sweltering heat and has disadvantage on all concentration and intelligence checks. Creatures who come in physical contact with his scales instantly take 5d10 fire damage, with a DC 20 dexterity saving throw to avoid a further 10d10 fire damage.

Ultrathermal. Damage dealt by Valestryx bypasses resistance to fire or radiant damage, and treats immunity as resistance.

Oversized Wingtips. When Valestryx is not flying, creatures may choose to target his wingtips rather than his central body, which have 27 AC but does not cause the effects of his Superheated Scales trait, nor his Blazing Sun ability. If his wingtips are hit while he is in flight, Valestryx must make a DC 20 dexterity saving throw or be knocked prone, falling out of the air.

Unerring Fury. Valestryx has advantage on all saving throws in relation to being charmed, stunned, paralyzed, petrified, poisoned, prone, restrained and unconscious. When in his Mythic state, he additionally gains +5 bonus to all rolls in the aforementioned categories.

Haltless (2/Long Rest). If Valestryx is at half health or above, and suffers an attack which would reduce him to zero or otherwise kill him, he channels his rage to ignore all damage and persists.

Bonfire. Valestryx sheds bright light in a 120-foot radius and dim light for an additional 120 feet. He cannot be invisible, and he cannot benefit from being in darkness or heavily obscured areas.

Multiattack. If Valestryx chooses to use Infernal Bite, Searing Talons, or Adamantine Slag, he makes three attacks, of any combination of the three.

Infernal Bite. Melee Weapon Attack: +19 to hit, reach 5ft, one target. Hit: 40 (6d12) piercing damage, plus 65 (8d12 + 15) fire damage.

Searing Talons. Melee Weapon Attack: +19 to hit, reach 25 ft, one target. Hit: 55 (12d8) slashing damage, plus 35 (4d12 + 10) fire damage.

Adamantine Slag. Ranged Weapon Attack: +19 to hit, range 10/100 ft, one target. Hit: 75 (12d8 + 20) fire damage. The target must make a DC 20 dexterity saving throw or become covered in slag, taking 8d10 fire damage on their turn for 1d4 rounds and suffering the restrained condition. A trapped creature may use its action to make a DC 24 strength check to break free.
A creature covered in slag cannot be targeted by this attack, and has +4 to all subsequent saving throws to avoid the slag for ten minutes after it is removed.

 Blazing Current (Recharge 5-6). Valestryx spews a concentrated blast of superheated fire energy in a 60ft cone. Each creature inside must make a DC 24 dexterity saving throw, or take 65 (8d10 + 20) fire damage and 40 (6d12) radiant damage.

Flare Burst (Recharge 3-6). When attacked, Valestryx can unleash a burst of flame, which adds +5 to his armor class during the attack roll, deflects any missile-based attacks, and removes all physical conditions. All creatures within a 30ft radius around Valestryx must make a DC 24 dexterity saving throw or take 80 (15d10) fire damage and be knocked back 20ft and sent prone, otherwise taking half damage and being knocked back 5ft without suffering the prone condition.

Valestryx can take 5 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. Valestryx regains spent legendary actions at the start of his turn.

Nova (Costs 2 Actions). Valestryx flares his wings, producing a massive shockwave. Each creature within 30 feet of him must make a DC 24 dexterity saving throw or take 17 (4d6 + 10) thunder damage and be knocked prone. Valestryx can then fly up to half his flying speed.

Sear (Costs 1 Action). Valestryx channels a gust of superheated air in a line 60 feet long. Every creature within 10 feet of the line must make a DC 24 constitution saving throw or suffer disadvantage on all attack rolls for ten minutes. Effected creatures may repeat the save with a bonus action on their turn, or cure it through cooling themselves down (I:E, throwing a bucket of water on themselves, casting cone of cold, etc...).

Endure (Costs 3 Actions). Valestryx focuses his wrath, knitting his wounds and purging himself of doubt. He regains 100 hit points, and ends one condition afflicting him.

Living Star. Upon being brought to half his hit points, Valestryx's true fire lights, causing him to explode outward with a greater heat than any other. His scales begin to glow a blinding white, liquid metal dripping from between them and out of his jaws. When Living Star activates, Valestryx recovers all lost health and releases a burst of fire outward. All creatures within 40ft are knocked away, as well as needing to make a DC 24 dexterity saving throw or take 28 (5d10) fire damage and be blinded until the end of their next turn.

Blazing Sun. When Valestryx is in his Mythic state, simply being in his presence is harmful. Any creature within 20 feet of him must make a DC 24 constitution saving throw at the end of its turn, or suffer increasingly negative effects.

1. Creatures who stand under 20 feet from him take 10 (2d10) fire damage.
2. Creatures which are within 10 feet take 25 (5d10) fire damage and suffer disadvantage on all ability checks.
3. Creatures that are within a 5ft radius around Valestryx take 55 (10d10) fire damage and 15 (3d10) thunder damage from the overwhelming blast of heat which he produces, in addition to disadvantage on all rolls. This does not apply to death saving throws.

Flame beyond Fire. All attacks Valestryx makes which involve fire damage deal an additional 18 (4d8) radiant damage and 18 (4d8) lightning damage, and require a further DC 20 wisdom saving throw to avoid being blinded until the end of its next turn. If a creature succeeds this saving throw, it no longer must make this save for 24 hours.

Absolute Inferno (3/Week). Valestryx begins to charge the ability, producing a visually obvious current of energy around his jaws. On his next turn, he unleashes a 120ft cone of fire energy, as a greater, wider form of his breath attack. Any creature that enters the area for the first time or starts its turn there must make a DC 24 dexterity saving throw, or take 10d10 fire damage and 5d10 radiant damage. 
On the turn following his unleashing of this ability, and upon all subsequent turns in which it was maintained, Valestryx may choose to expend his action to "focus", maintaining Absolute Inferno's area and damage, and allowing him to point it in a new direction of his choosing. Additionally, for every round after its initial activation, Absolute Inferno gains 10d6 fire damage and 6d6 radiant damage, as well as causing unique effects.

1. After two rounds of use, Absolute Inferno does 20d6 additional fire damage and 12d6 radiant. The save DC becomes 26.
2. After three rounds of use, it deals 40d6 fire and 24d6 radiant damage, and begins to melt metal, causing damage to any nonmagical metals caught in its blast. It becomes a DC 28 save.
3. After four, Absolute Inferno has an additional 80d6 fire damage and 48d6 radiant damage, destroys all nonmagical metals in its area of effect, and begins to damage magical metals. Only a 30 or higher can avoid it.
4. After five it does 160d6 fire damage, 96d6 radiant damage, destroys magical metals, and begins to melt magical shields, resistances, and all other forms of arcane defense. A total of 32 or higher is required to avoid the blast.
5. After six rounds of pure focusing, Absolute Inferno deals 320d6 fire damage, 192 radiant damage, and destroys all forms of magical shielding to exist. Its save DC becomes 34.
6. For all rounds following, the DC increases by two, and any creature which fails is instantly and completely annihilated at the subatomic level.

While concentrating on Absolute Inferno, Valestryx's movement speed is halved. If Valestryx takes over 100 damage from a single attack, is stunned, petrified, paralyzed or goes unconscious, his concentration will break and he will be forced to dispel Absolute Inferno.