Cursed Druid Guardian (spirit)

Two-Realm Presence. If the Cursed Druid Guardian (spirit) drops to 0 hit points, it is not defeated. Instead, it freezes in place, invulnerable, and may be easily revived by the Cursed Druid Guardian (physical). Only if both are reduced to 0 hit points at the same time does it dissolve into dust.

Multiattack. The Crused Druid Guardian (spirit) makes two Eldritch Blast attacks or two Staff attacks.

Eldritch Blast. Ranged Spell Attack: +7 to hit, reach 30 ft., one creature. Hit: 5 (1d10) force damage.

Quarterstaff. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 5 (1d6+2) bludgeoning damage, 6 (1d8+2) bludgeoning damage if wielded with two hands.

Revitalise. If the Cursed Druid Guardian (physical) drops to 0 hit points, the Cursed Druid Guardian (spirit) can spend its action to begin a spell. Before casting Revitalise The Cursed Druid Guardian (physical) uses its reaction to cast Shield If its concentration is not broken before the beginning of its next turn, the Cursed Guardian (physical) reawakens with 2d12 hitpoints restored.

Curropted Blast: If the Revitalise spell fails the Cursed Druid Guardian (spirit) channels his cursed energy into a powerful explosion of force energy. Each creature in a 15-foot cone must make a DC 16 Dexterity saving throw, taking 21 (6d6) force damage on a failed save, or half as much damage on a successful one. Additionally, creatures hit by this attack must succeed on a DC 16 Constitution saving throw or become stunned. A creature can repeat the saving throw at the end of each of its turns, ending the stunned effect on itself on a success. 

The guardian can take 1 legendary action, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The guardian regains spent legendary actions at the start of its turn. 

Reactionary Attack: If it is not concentrating on Revitalising the Cursed Druid Guardian (physical), The Cursed Druid Guardian (spirit) can make one Eldritch Blast attack as a reaction against a creature that attacks it.