Feral. This creature cannot be charmed or frightened.

Spellcasting. The Abyss Wanderer is a 1-level spellcaster. Its spellcasting ability is charisma (spell save DC 13, +3 to hit with spell attacks). The Abyss Wanderer has following Sorcerer spells prepared:
Cantrips (at will): Chill Touch, Poison Spray 
1st level (3 slots): Shield, Sleep 

Multiattack. This creature can make two attacks with its claws.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit: (2d8) slashing damage.

Greatsword. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit: (2d6+3) slashing damage.

Abyssal Shriek. This creature can let out a shrilling scream, and any conscious creatures within 30 ft. of it must make a DC 15 constitution saving throw. On failure, that creature is frightened for one turn and takes 5 psychic damage. On success, that creature is not affected. This bonus action has a cooldown of four turns.

Feral Rage. Before making an attack, this creature can decide to gain advantage on the attack, at the cost of losing 3 AC until their next turn.

 Crazed mind. This creature chooses one target it can see within 30 ft. That creature must make a DC 15 constitution saving throw. On a failure, the target's next attack is skewed. On a success, nothing happens. Do not inform the target of the DC, or if they passed the save (as to avoid metagaming). Cooldown of two turns. (Skewed attack is defined as follows: When you make your next attack, roll a die with at least as many faces as creatures within walking speed, or your attack's range, whichever is farther. Proceed to attack the creature that number lands on, teammates included. Reroll if you land on your original target's number.)

Opportunity attack. If a creature leaves melee range, this creature may make a melee attack on that target.