Elder Elemental (Phoenix)

Disclaimer: This subclass is not properly balanced and as such is probably far too powerful or weak. Also, I'm not good at this so you will have to keep track of the features yourself.

Phoenixes are described by many sages as champions of good, and by others as random agents of destruction. Most accounts agree that phoenixes are reclusive creatures that do not seek out contact or conflict with other creatures, but, if disturbed, provoked, or properly motivated, show relentless fury and destructive power.  Phoenixes can be found in the deepest reaches of the Elemental Plane of Fire and in remote locations in Elysium. As reclusive creatures, they tend to avoid contact with others however more open phoenixes often make pacts with people giving great power over healing and flames.

Bonus cantrips

At 1st level, you learn the Thaumaturgy and Fire Bolt cantrips. They count as warlock cantrips for you, but they don’t count against your number of cantrips known.

Rising from the ash

When a creature is reduced to 0 hit points you can spend your reaction to restore that creature to 1 + your charisma modifier (minimum 1). This can only be used a number of times equal to your warlock level until completion of a long rest.

Fly speed

You gain a flying speed equal to your walking speed. This can't be used with heavy armour.

Blazing lusture

Starting at 6th level, your link to the Phoenix allows you to serve as a conduit for incandescent energy. You have resistance to fire damage.

Fate of the flames

Starting at 6th level, you can call on your patron to alter fate in your favour. When you make an ability check or a saving throw, you can use this feature to add a d10 to your roll. You can do so after seeing the initial roll but before any of the roll's effects occur. This becomes 1d12 at 10th level and 1d20 at 16th level.

Warning: Falling Magma

At 10th level, you can cast hellish rebuke as a 5th level spell without expending a spell slot.

Armour of flames

At 10th level your AC becomes 15+dex. (max. 3) permanently and you gain resistance to 1 damage type of your choice except for necrotic, radiant or fire.

Eruption of power

From 14th level onwards on each successful death saving throw, all creatures in a 5-foot radius make a dexterity saving throw. On a failed save each of those creatures take 2d8 fire damage. When your death saving throws are successful you can make a DC 15 constitution saving throw. On a success, you regain hit points equal to the total fire damage dealt by this feature.

Through the fire and the flames

Starting at 14th level, when you hit a creature with an attack, you can use this feature to instantly transport the target through the Elemental Plane of Fire the creature disappears while they fly through a nightmarish landscape of eternal flames. At the end of your next turn, the target returns to the space it previously occupied or the nearest unoccupied space. If the target is not a fire-based creature it takes 10d10 fire damage as it burns from its torture. Once you use this feature, you can't use it again until you finish a long rest.