You have perfected your assassin’s strike. The extra damage from your Strike from the Dark feature increases to a number of d8s equal to your proficiency bonus (instead of that number of d4s), and you deal an extra 2d8 damage if the target is in dim light or darkness (instead of an extra 1d4 damage).
In addition, when you deal damage using Strike from the Dark, you can use your reaction to burn a seal on the creature, causing them to be blinded for 1 minute instead of dealing the seal’s damage.
Shadows are your companion, aiding you in your exploits. You gain the following benefits:
You gain darkvision out to 60 feet. If you already have darkvision, its range increases by 60 feet.
Your movement speed increases by 10 feet.
You have advantage on Dexterity (Stealth) checks made to hide. Whenever you make a Dexterity saving throw to take only half damage from an effect, you instead take no damage if you succeed on the saving throw, and half damage if you fail.
Interdicted creatures radiate darkness in a 10-foot radius. Mundane sources of light can’t illuminate this darkness, but creatures with darkvision can see through it. If any of this darkness overlaps with an area of light created by magic or psionics, the overlapping area of darkness is illuminated by the light.
Whenever you roll a 1 or 2 on a die to determine the damage of your seals or your weapon attacks against interdicted creatures, you can reroll the die and must use the new roll.
As a bonus action, you can expend a seal to become invisible for 10 minutes or until you attack or cast a spell.
As a bonus action, you can call on the shadows to entrap a creature you can see within 30 feet of you. The target must make a Charisma saving throw, made with disadvantage if they are in dim light or darkness. On a failed save, the target’s speed is halved and they can’t willingly move more than 30 feet away from you. This effect ends for the target if you are incapacitated or die or if the target is more than 30 feet away from you.
As an action, you can cast the disguise self spell without expending a spell slot.
You understand the power of striking from the shadows. Once per turn, when you hit an interdicted creature with a melee weapon attack and you have advantage on the attack roll, you can roll a number of d4s equal to your proficiency bonus and deal extra damage equal to the total you rolled. This damage increases by 1d4 if the target is in dim light or darkness.
You are particularly skilled against foes you mark for death. You have advantage on your first attack against an interdicted creature on each of your turns.