Cataclysm

Whether your sorcerous origin was a sign for the end times, survived some sort of impending doom, or the unstable elements have graced you with painful uncontrollable power, your awakening was a sign of worldly changes.  The primordial chaos surges within you, and every moment of breaking down and getting back up again made you a force to be reckoned with.  Whether the commoners praise or kneel in fear, you bring with you a path of destruction in your wake.

Rebuke the Violent

1st Level Cataclysm Sorcerer Feature

Beginning at 1st level, whenever you roll initiative and are not surprised or incapacitated, you may immediately use your reaction to cast a spell that has a casting time of one action. The spell can be of a level less than or equal to half your sorcerer level, rounded down.

Ruinous Soul

1st-Level Cataclysm Sorcerer Feature

At 1st level when you select this feature you're able to awaken a cataclysmic force that empowers yourself and your magic to unyielding elements.
Whenever you cast a spell of first level or higher, choose a manifestation. Your spell can deal damage of the chosen manifestation's elements if it is a damage spell, and you become resistant to the elements of that manifestation until the start of your next turn.

Conquest:  Spells you cast can instead deal radiant or force damage, and you also gain resistance to both.
Pestilence:  Spells you cast can instead deal acid or poison damage, and you also gain resistance to both.
War:  Spells you cast can instead deal fire or lightning damage, and you also gain resistance to both.
Death:  Spells you cast can instead deal necrotic or cold damage, and you also gain resistance to both.

Cataclysm Casting

6th-Level Cataclysm Sorcerer Feature

You're able to tap into your inner vindictive will to empower your spells and metamagic to disastrous effects, even at the expense of your own body's vitality.

After you successfully hit a creature with a damage spell or after a creature fails a saving throw against your spell's damage, instead of rolling damage you may instead deal the maximum possible that can be rolled. You lose hit points equal to 3 times the spells level (minimum of 3 if it is a cantrip) and you regain a sorcery point.

If Cataclysm Casting would reduce you to 0 hit points, it instead reduces you to 1 and you cannot Cataclysm Cast until you regain hit points. If the spell is an area of effect, this feature can only apply to one creature that fails the saving throw against taking damage.

Painful Deliverance

14th-Level Cataclysm Sorcerer Feature

You've grown a body accustomed to the ever changing ruinous soul within you. You gain the following benefits:

• Resistances from your Ruinous Soul now become immunities.
• Spells transmuted to different damage types with Ruinous Soul overcome enemy resistances.
• You gain an additional sorcery point every time you use your Cataclysm Casting feature.

Pinnacle of Absolution

18th-Level Cataclysm Sorcerer Feature

At 18th level, you become a harbinger of destruction, beyond death. If you drop to 0 hit points and do not die outright, you do not fall unconscious. Instead, you enter a state of absolution for one minute and treat all spells as if they were Cataclysm Cast until this feature has ended. You cannot regain hit points while in this state, and once your Absolution has ended, you fall unconscious and enter the dying state as normal. Pinnacle of Absolution ends early if you did not cast a spell since the end of your last turn. Once you've fallen to 0 hit points this way, you cannot use this feature until you finish a long rest.