The Great Tree

Otherworldly Patron
Comments from the Knuckle: “When three different members of the team come to the same concept, it should probably get written. 
     For me when I think of a warlock sworn to a Great Tree, the first thing that comes to mind are the Spriggans from Skyrim. Holy crap, every time I run into one, I book it in the other direction. Those guys are terrifying to me. So when designing a subclass built around being a nature-themed spellcaster/warrior, those were the first things that leapt to mind as a way to convey a nature theme in the sinister thematic niche that the warlock holds.
     It was also inspired by one of my players who said to me, ‘how do I tank…as a warlock?’ My first response was, of course, fiend, but they were quick to say, ‘no. I have not made a deal with the devil. Not with this warlock.’ So, to me the Great Tree was an interesting place to explore a durable warlock in a more neutrally-aligned thematic space.”

The Great Tree

The inimitable princes of the Feywild are not the only source of power in the enchanted forests and magical jungles of that realm — indeed, there are many good reasons why a prospective warlock might not wish to deal with them. Far more stable and reliable partners can be found in the towering, ancient trees of the Feywild, whose roots reach back to the ancient past, and whose branches span to the end of time.
     Although journeying out into the woods to find a Great Tree with which to form a pact can be dangerous, the rewards are clear: these patrons are generous with their power, seeking to nurture their mortal charges, guiding and pruning them until they are fit to serve as guardians of the forest.

The Great Tree Expanded Spells

Spriggan
Starting at 1st level, you can use your bonus action to assume the form of a primal force of nature. Your body becomes covered entirely in bark, any hair you have becomes leaves and moss, your eyes glow amber, and you sprout a twisting pair of branch-like antlers. This form lasts for 1 minute, or until you dismiss it (no action required). For the duration, you have the following benefits:

• Your AC equals 13 + your Constitution modifier.
• Your fingers twist into sharpened roots which can be used as natural weapons, dealing 1d4 slashing damage on a hit.
• You have advantage on Dexterity (Stealth) checks made while in a forest.
• You gain temporary hit points equal to your Charisma modifier when you enter this form. 

     You can use this ability twice, and regain all expended uses when you finish a short or long rest.

Creeping Roots
Starting at 6th level, when a hostile creature that you can see within 30 feet of you attacks one of your allies, you can use your reaction to ensnare them. Immediately after the attack, you slam your arms into the ground, and they transmute into twisting roots that ensnare the hostile creature. That creature must make a Strength saving throw against your warlock spell save DC. On a failed save you drag it to an unoccupied space within 5 feet of you.
     Once you use this ability, you can’t use it again until you finish a short or long rest.

Wildwood Guardian
Starting at 10th level, you are immune to disease, and when you use your Spriggan feature, you gain the following benefits:

• You gain temporary hit points equal to 5 + your Charisma modifier at the start of each of your turns.
• You have resistance to poison damage, and advantage on saving throws against being poisoned.

Ironwood
Starting at 14th level, while using your Spriggan feature, you have resistance to bludgeoning, piercing, and slashing damage.

Eldritch Invocations
If an eldritch invocation has prerequisites, you must meet them to learn it. You can learn the invocation at the same time that you meet its prerequisites.

Spriggan Magic
Prerequisite: Spriggan feature
You learn the druidcraft and shillelagh cantrips. These cantrips count as warlock spells for you. In addition, you can target your claws with shillelagh, treating both hands as one weapon. Starting at 5th level, you can make an additional attack with your claws as a bonus action, adding your ability modifier to the damage.

Changelog: 11/4/2017: Creeping Roots: Added saving throw
Spriggan: changed to twice per short rest.
11/5/17: Spriggan Magic: Modified wording and moved the bonus action attack to 5th level.