Reaper

Mortals birthed, cursed of blessed by the gods with unusual abilities.

Mark

When you choose this subclass at third level you gain the ability to silently mark one creature. At the cost of a turn, you magically and silently mark a the weapon you currently have equipped for 10 rounds (60 seconds). The next person stuck by this weapon within that time-frame will have a mark bloom upon their body visible only to you. Gain advantage on attack rolls and perception checks to find the marked target for 5 rounds (30 seconds). In addition you have rough estimate knowledge of the direction and distance of the marked target for the duration of the mark and advantage on survival checks to track previously marked targets.

This ability can only be used a number of times equivalent to your wisdom modifier (1 minimum) per long rest and while applying the mark to your weapon the player's movement is restricted. You may still use reactions the turn you use this ability. You regain all uses of this ability on a long rest. You may only have one creature marked at a time.

The player in addition has a spiritual weapon which is magically bound to character and will return to hand if left past 30 ft from the character. The player is proficient with the weapon which is chosen. The weapon is a representation of the characters soul and personality and will reform if ever destroyed in 1d6 days. For the duration that the weapon is reforming the player may only use the mark ability once per long rest despite wisdom modifier and is unable to become ethereal. The weapon is finesse (if melee) as well as magical for purpose of bypassing physical damage resistance or immunity. The spiritual weapon cannot be changed once it is chosen i.e you cannot turn it into a bow if you have already chosen a rapier and vice versa.

Terror & Silence

Starting at 9th level when you unstealth or come out of invisibility you can choose to activate Terror. You have 4 charges of Terror which increase to 6 at 15 then 8 at 17. Choose 1 enemy of size small, medium, or large,within your movement range, which must make a (DC 10 + your dexterity modifier + your proficiency bonus) wisdom saving throw upon activation of terror. If they fail they are frightened until the end of your next turn. Your critical role range for frightened characters is 18 - 20.

You also learn how to cast the spell Silence.

Phantom Undertow

Beginning at 13th level you can become ethereal once per long rest as a bonus action till the end of your next turn.  Taking the attack action while ethereal will result in this ability being ended early.

Necrotic Critical

Starting at 17th level you gain the ability to reap a soul one per Long Rest that has been or is currently marked.  The target must be in vision and within your movement range. When Grim Reaper is activated you rapidly move behind them to perform an attack roll. Upon rolling a crit the target must make a wisdom saving throw (10+ wisdom modifier+ proficiency bonus). If the target fails, they either suffer and extra 10d10 necrotic damage in addition to other damages dealt or die if their hp is below 100 hp before damage calculation.  If the player fails to roll a crit but still manages to hit simply apply normal damages including sneak attack if applicable.  Huge or gargantuan creatures are dealt 10d10 necrotic on a failed save regardless of their hp threshold.