The Zaratan

This subclass is 1 of a set of 4 being developed, one for each elder elemental as an optional patron of elemental power (including a rework of the phoenix already out there).  All aspects of my classes are somewhat derived from other spells or warlock abilities and should be quite balanced.  However, I'm open to suggestions.

You have bound yourself to an elder elemental known as the Zaratan. The Zaratan is a hulking, armored reptile, its shell composed of the very landscape from which it arose.  Its footsteps shake the land to its foundations as it inflexibly moves forward in a path of destruction, stubbornly grinding down all in its path. It bestows upon you the power to do the same, and can be pleased by attitudes of stoicism, endurance, and unyielding resolve. Deliberate and slow to act, but inflexible once a path is chosen.  Let nothing stand in your way.

Expanded Spell List

The Zaratan lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Zaratan Expanded Spells

Spell Level	Spells
1st	catapult, earth tremor
2nd	enlarge/reduce, maximilian's earthen grasp
3rd	erupting earth, meld into stone
4th	stone shape, stoneskin
5th	passwall, wall of stone

Zaratan's Approval

Bonus Proficiency: You gain proficiency with shields and medium armor.

Bonus Cantrip: mold earth 

Starting at 1st level, any attack in which you required your shield to successfully block the damage, you gain temporary hit points equal to your Charisma modifier + your warlock level (minimum of 1).

Absolute Defense

Starting at 6th level, you gain a number of d6s equal to your Charisma modifier which can be used to at any time to boost defense until the start of your next turn.  This boost may also trigger Zaratan's Approval if it causes the attack to be blocked.

You regain expended dice after a short or long rest.

Bulwark

Starting at 10th level, as a bonus action you can create a tower shield made of earth and stone. This shield counts as a shield +1 granting 3 AC normally and 4 AC when used as a two-handed item. When the shield is used in a shove attack the target takes an additional 1d4 piercing damage and is magical for the purposes of overcoming resistance. The shield lasts until it leaves your grip at which point it crumbles to dust.

Boulders of Destruction

Starting at 14th level, as a bonus action you may summon the boulders of destruction for 1 minute, which requires concentration as if casting a spell. The very earth around you begins to form into a floating bolder in an empty space near you and moves with you.  For the duration, you may use an action to hurl a boulder targeting a 10 ft cube within 60 feet in which targets would make a Dexterity saving throw. Each target takes 6d6 bludgeon damage on a failed save, or half as much on a successful one.  The boulder counts as both magical and siege. After each boulder is thrown another one immediately begins forming in its place. This feature ends when the duration expires or when a total of 6 boulders have been thrown. This amount increases to 7 at level 17, and 8 at level 20.

Once you use this feature, you can’t use it again until you finish a long rest.