patron - the shell

The Shell
You have made your pact with a powerful being that possesses a shell resilient enough to block any strike. Your patron might be an ancient dragon turtle that has slumbered at the bottom of the ocean for centuries, a colossus formed out of the hardest metals and rocks making up the core of the planet, or another similar creature. Alternatively, your patron's shell might not be a literal shell, but still a defensive part of them that they almost always have; they might be an automaton with a body made out of an unbreakable metal, or they could be a death knight that wears armor made out of the hardest steels known to man.
Expanded Spell List
The Shell 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.
1st - heroism, shield
2nd - aid, enlarge/reduce
3rd - protection from energy, spirit guardians
4th - death ward, fire shield
5th - Bigby's hand, wall of stone
Shell Armor
When you choose this patron, at 1st level, you gain the ability to form or retract a magical armor on your body, made from your patron's shell, as a bonus action. When your shell armor is formed, your AC is equal to 12 + your Constitution modifier. While you're wearing your shell armor, any critical hit against you becomes a normal hit.
Additionally, your hit point maximum increases by 1 and increases by 1 again whenever you gain a level in this class.
Immovable Mountain
Starting at 6th level, your patron grants you the ability to prevent yourself from being moved. You have advantage on ability checks and saving throws against being forcibly moved, and as an action, you can enter an immovable stance until the start of your next turn. While in your immovable stance, your weight increases by eight times, no creatures can pass through your space, and you cannot be moved by anything except gravity.
Defender's Body
At 10th level, your skin reinforces itself with an iron-like sheen. At the start of each of your turns, you gain temporary hit points equal to your warlock level. Also, when a creature within 30 feet of you takes damage, you can use your reaction to magically take that damage, instead of the creature. This feature doesn't transfer any other effects that might accompany the damage, and the damage can't be reduced in any way.
Iron Sentinel
By 14th level, you have learned how to temporarily channel all of your patron's power into yourself, as an action, for 1 minute, while your shell armor is formed. While you do so, you have the following benefits:
- Your AC is equal to 15 + your Constitution modifier.
- Your gain the enlarge benefits of the *enlarge/reduce* spell.
- Your Defender's Body feature increases its number of temporary hit points by 10.
After using this feature, you must take a long rest before doing so, again.