Actions

Multiattack The Revenant makes two Doom Bell attacks and one Chains of the Damned.
Doom Bell Mellee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 2d8+3 bludgeoning dmg and 2d6 psychic dmg. Target must succeed a DC 14 WIS Save or be Stunned until the end of its next turn.
Chains of the Damned Melee Spell Attack: +6 to hit, range 30 ft., one target. Hit: Target is grappled (escape DC 16) and Restrained and takes 3d6 necrotic dmg at the start of each of its turns.
Dolorous Knell (Recharge 5-6) The Revenant rings its bell violently, sending waves of despair in a 60 ft. radius. Each creature must make a DC 14 CHA Save. Fail = 6d6 psychic dmg and target is Frightened for 1 min, Suc = 1/2 dmg. A Frightened creature repeats the save at the end of each of its turns, and a success makes it immune to the Dolorous Knell.

Bonus Actions

Aura of Sorrow. The revenant activates or dispels a shadowy aura of dark energy. While active in a 30 ft. radius around the revenatn, non-undead creatures that enter the aura for the first time on a turn or start their turn there, must make a DC 14 WIS Save. On a fail, the creature has Disadvantage on ATK rolls & Ability Checks. The creature can use an Action to repeat the Save, ending it on a success. A successful save makes the creature immune to the revenant's aura for the next 24 h.

Reactions

Counterspell (1/day) at lvl 4