Feyhome Mark

The fey lords may or might not choose for themselves who might be their favorite - yet the Wild will deal with those who would deny their favorites the right to continue to choose how they walk the worlds.  A coalescence of magic adds starlight to one's spirit, enough that eventually it takes root in mortal bones.  

The Wild is your Home, and nothing will gainsay it.

REQUIREMENT

An Oath to the principles of a greater Fae power, equally imbued with their direct knowledge of you and your intense mortal insistence to the Oath you share - for the Wild knows it, and enforces, that oaths go both ways.

The Affinity Grows 

...as the power of the recipient does, for in truth it is their own insistence upon the entwining of spirits and choices that makes it even possible. 

Scales four times at levels 4, 8, 12, and 16.  If a feyhome mark exists on someone who is of a lesser level, remember that it still represents an affinity to a being of Power, and those who recognize it may act accordingly.

This Feat is expected to represent the Fae equivalent of Dragonmarks in campaigns with a more arcane or wilderness focus.  It is entirely within the GM's scope to allow selection of this feat only at the first chance, or to have its effects replace all Feat slots, to use them to replace Optional Class Features, or to replace a character's originating Background with only memories of the strengthening bond.  Use Factions to represent how well known your bond becomes, or how easily the mark of magic is seen upon you.

If Ever Deliberately Oathsworn to A Foe

The archfey and indeed many Fae are creatures of intrigue, often whether they intend it or no. If the bearer of this favor ever become oath-broken to their archfey, the Mark will begin to fade, first losing the deepest aspects of its powers, and then fading away entire.

If the favored soul is sworn to another who is the archfey's foe, the power will fade away one level at a time at a pace determined by the game master.   If they have chosen to be Foe to their oath-partner, the starlit power will break immediately and completely.

Your oath partner will be aware you are oath-broken, although probably not how (unless told) and it's entirely up to their nature and whether they are Seelie, how simple, fantastical, complex, or whether it's even possible to recover their favor.  

What it won't be?  It won't be easy.

KINSHIP

Magic

Each level of the Mark allows an oathsworn to accept one (1) of the following minor racial traits found of the elven kindreds and greater Fae. They will not change once acquired. 
At the game master's option, the same can be selected again, in which case they stack, improving speed, range, or bonuses as applicable.

• quick magic: one Wizard cantrip.
• slow magic: Ritual Casting spells can be learned through adventure without class binding and with context, but the spellcast takes 1 hour.
• weapon affinity: proficiency in the four classic elven weapons - shortsword, shortbow, long sword, longbow.
• weapon intensity: +1 attack and damage with the four classic elven weapons - shortsword, shortbow, long sword, longbow.
• keen eyes: proficiency in Perception
• keen senses: +1 Perception when already proficient
• night eyes: Darkvision at 40 feet.
• fair of form: +1 to a single ability score - either DEX or to the stat (INT, CHA, WIS) aligned to the fey lord who is so fond of their oathsworn or whose noble House they have bonded with.
• slip away: Misty Step at range 15 feet only, at will.

Speak For Yourself

Each level of the Mark allows the oathsworn to accept one of the following languages known by the elven kindreds and greater Fae. 
The oathsworn may not learn the language if their archfey Patron does not know the language.  
They do not gain additional language options if they already know these languages.

This does provide a way for the oathsworn to learn Common, if for reasons of background and good RP they do not know the language.

• Elven
• Sylvan
• Primordial
• Celestial
• Common

Rest Protected

Each level of the Mark increases the passive defenses provided for the oathsworn's good health at rest.

• (4th level) Cannot be surprised while asleep.
• (8th level) Rest aware in trance as many fae kindred do, requiring 2 hours less rest than your species does to complete a Long Rest.
• (12th level) Age more slowly - rest does not count against your lifespan.
• (16th level) If slain the oathsworn's body cannot be forced to be undead without their willing spirit.  With willing spirit, they cannot be corrupted; their alignment is theirs, their soul is their own to command.

Enchantment Wary

Each level of the Mark increases the passive defenses provided for the oathsworn's mental condition.  If one already has Advantage for these circumstances by other means, +2 is provided.

• (4th level) +2 to saves against being Charmed or any enchantment spells.
• (8th level) Advantage on saves against the Charmed condition (this replaces the +2)
• (12th level) +2 to saves against All spells (this replaces the school limitation).
• (16th level) Advantage to saves against All spells (replacing all the previous) and for spell attacks which deal damage, a 40% reduction of the damage done.

Oath Enforcement

Each level of the Mark increases the ability of the oathsworn to actively support the oath in respect for their devotion in its implementation.

• (4th level) Gain an Action Surge usable to enforce the nature of the Oath.  It is usable as a Bonus Action and does not replace or use up any similar power the oathsworn may already have from feats, training, their class, or story awards.
• (8th level) The Help Action has a range of 30 feet to support someone who is acting on behalf of the Oath.
• (12th level) Cannot be compelled to act against the Oath.  This prevents the sworn soul from becoming oath-broken via compulsion or duress.
• (16th level) Action Surge for oath enforcement may be used as a Free Action, no longer requiring expenditure of a Bonus Action. 

Health To You

Each level of the Mark passively focuses the oathsworn's determination into their body, intrinsically gathering fey starlight in their being.  
This affects base hit points.

At the game master's option, this may impact usage of a hit die for other purposes if the place one is at is sufficiently Fey, friendly to the noble archfey Patron, or somehow a place of power that actively supports the nature of the PC's Oath.

• (4th level) Hit dice are a minimum value of 2.
• (8th level) Hit dice are a minimum value of 4.
• (12th level) Hit dice are a minimum value of 6.
• (16th level) Hit dice are a minimum value of 8.
  
  

The Legend Grows

If your campaign supports levels beyond 20, consider having Epic Boons, supernatural gifts, or legendary qualities reflect how the oath was carried throughout their mortal life, or uplifting them to agelessness (see chapter 7, DMG, Other Rewards).