Siphoning Fist

Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) bludgeoning damage plus 5 (2d4) psychic damage. The target must succeed on a DC 13 Charisma saving throw or its hp maximum is reduced by an amount equal to the psychic damage taken. The woe siphon regains hp equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hp maximum to 0.

Cause Despair

The woe siphon can overwhelm a creature with intense feelings of inadequacy. One creature the woe siphon can see within 60 feet of it must succeed on a DC 13 Charisma saving throw or become overwhelmed with despair for 1 minute. A creature overwhelmed with despair has disadvantage on ability checks and attack rolls. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to this woe siphon's Cause Despair for the next 24 hours.

Invisibility

The woe siphon magically turns invisible until it attacks, or until its concentration ends (as if concentrating on a spell). Any equipment the woe siphon wears or carries is invisible with it.