Your pact draws on the power of the Shadowfell, a desolate plane which mirrors the Fae Wild and siphons its magic. You might forge a bargain with Moriahthane, goddess of the cursed waters and plague, or Marilka, patron of travelers and loyal follower of Moriahthane
LEVEL 3: SHADOWFELL SPELLS
The magic of your patron ensures you always have certain spells ready; when you reach a Warlock level specified in the Shadowfell Spells table, you thereafter always have the listed spells prepared.
LEVEL 3: SHADOW METER
Stress, damage taken, damage dealt and magic use all contribute to the Shadow meter. The meter begins at 0 and builds up to 25. When it reaches its max, you involuntarily begin to enter your Shadowstate. The meter builds and reduces in the following ways:
The meter reduces itself by half (rounded up) when you take a short rest and fully reduces itself at the end of a long rest.
LEVEL 3: MISTY VISIONS
At the beginning of your turn there is a chance you have a shadowy vision of the future. This is the will of the Shadowfell and appeases it upon fulfillment. The DM will describe to you a set of actions or circumstances that you may attempt to bring to fruition in order to subtract 1d6 plus half your current warlock level (rounded up) from your shadow meter. These actions may help or hinder your party, but cannot be directly harmful to you or your allies.
LEVEL 3: SHADOWSTATE
When your Shadow Meter reaches is maximum value, you begin to transform into the Shadowstate. If this transformation is the result of a spell slot expenditure, increase the level of the spell cast by 1. As a reaction, you may teleport to a home sigil in an attempt to prevent this transformation. If not, you lose control of yourself as your body creaks and groans into its Shadowfell altered state. You grow several feet taller and assume the description of the Shadowstate (see Shadowstate stat block). You may not take actions, bonus actions or reactions outside of those described in the Shadowstate's Madness of the Shadows trait. This transformation only ends under the conditions specified in the Shadowstate's Implosion trait. While in Shadowstate, you maintain concentration.
LEVEL 6: SHADOW STEP
As a bonus action, you can magically teleport up to 30 feet to an unoccupied space you can see. You can use this trait a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest. When you use your Shadow Step, one creature of your choice that you can see within 5 feet of you before you teleport must succeed on a Wisdom saving throw against your spell save DC or be frightened of you until the end of your next turn.
LEVEL 6: SHADOW INFLUENCE
You can allow the shadows to grow darker around you or an ally, potentially causing an attack to miss. When you or a creature you can see within 30 feet of you are hit by an attack, you can take a Reaction to reduce the number rolled by your Warlock level minus half the current value of your Shadow Meter (rounded down). Then increase your shadow meter by the amount reduced. You can use this feature a number of times equal to your proficiency bonus.
LEVEL 10: IMPROVED SHADOWSTATE
Now when you transform into your Shadowstate, your size is Large instead of Medium. You MAY also attack a third time when your Shadowstate uses its Multiattack. The maximum value of your Shadow Meter is increased to 40.
LEVEL 10: IMPROVED INFLUENCE
Now when you use your Shadow Influence feature, if the amount reduced reaches 0 due to subtracting half your Shadow Meter, you can instead subtract a fourth of your current Shadow Meter's value (rounded up). Then increase your Shadow Meter by the amount reduced.
LEVEL 14: SHADOW MASTERY
You have learned to harness the shadows that surround you, molding them to your needs. When gaining or reducing your Shadow Meter by any means (including those described in your Shadowstate) you may also choose to gain or reduce that value by half your Warlock level. If you gain meter this way, deal the amount gained as necrotic damage to a creature within 60 feet of you. If you reduced meter this way, gain the amount reduced as temporary hit points.