Darkness is a fickle thing; attempting to spread, whether through corruption or literally spreading darkness by removing all light.
Sometime in your life, you made a pact with this ever-present force. In return for the power to fight and kill, you will spread the shadow's influence in everything you encounter. The Umbra 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: At 1st level, you learn the shadow shape* cantrip if you don't know it already. In addition, you can communicate with an undead regardless of whether you share a common language. Starting at 1st level, shadows can wreathe you in sharpened form. As an action, you can surround yourself in a ring of shadows until the end of your next turn. These shadows create a 10-foot radius circle around you, heavily obscuring the area to all creatures outside it. A creature that steps into the circle must make a Dexterity saving throw, taking slashing damage equal to 1d10 + your warlock level on a failed save, or half that on a successful save. Once you use this ability, you can't do so again until you finish a short or long rest. At 6th, 10th and 14th levels, you gain an additional use of this ability between rests. Beginning at at 6th level, the darkness you use to surround yourself can protect you and help you maneuver. If you are in dim light or darkness, you can use your action to generate a ward of darkness over yourself. You gain temporary hit points equal to your warlock level. While you have these temporary hit points, you have resistance to bludgeoning, piercing and slashing damage, and vulnerability to radiant damage. Starting at 10th level, you gain the ability to move unseen between and through darkness. If you are in dim light or darkness, you can use your action to teleport up to 60 feet to an unoccupied space that is also in dim light or darkness. In addition, while you are in dim light or darkness, you are considered invisible to creatures without darkvision as long as you don't make an attack or cast a spell on your turn. At 14th level, your wounds bleed darkness. If you take damage equal to or higher than twice your warlock level from a single attack, you can use your reaction to regain an expended warlock spell slot.
"Shadow" by Kalen Chock Spells denoted by an asterisk are not found in official material and can instead be found in Thudnfer's Unparalleled Umbra Spell PackOtherworldly Patron: The Umbra
Expanded Spell List
Umbra Expanded Spells
Spell Level
Spells
1st
dissonant whispers, inflict wounds
2nd
dusk lance* , phantasmal force
3rd
phantom steed, shadow storm*
4th
phantasmal killer, umbral grasp*
5th
nightmare* , plated veil*
Dark Bargain
Shade Knight
Umbral Resilience
Darkstep
Lord of Twilight
Art Credit