Actions

Multiattack. The Guard makes two attacks, either a Crackling Backhand or Enflamed Stomp and a Slam attack.   Crackling Backhand. Melee Weapon Attack: +16 to hit, reach 15ft., one target. Hit: (3d12 + 10) lightning damage.   Enflamed Stomp. Melee Weapon Attack: +16 to hit, reach 10ft., one target. Hit: (3d10 + 10) fire damage.   Slam. Melee Weapon Attack: +16 to hit, reach 15ft., one target. Hit: (3d8 + 10) bludgeoning damage.   Prismatic Beam. The Guards internal crystal unleashes energy in a 60-foot line. Each creature in that area must make a DC 18 Dexterity saving throw, taking 40 (10d8) damage on a failed save, or half as much damage on a successful one. The damage is determined by rolling a d6:

1. Acid
2. Cold
3. Fire
4. Lightning
5. Necrotic
6. Poison

Legendary Actions

The Guard can take 3 legendary actions, 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 Guard regains spent legendary actions at the start of their turn.  

• Slam Attack. The Guard makes a slam attack.
• Of Sparks and Embers (Costs 2 Actions). The Guard can make either its Crackling Backhand or Enflamed Stomp attack.

Lair Actions

On initiative count 20 (losing initiative ties), the Guard can take a lair action to cause one of the following magical effects; the Guard can’t use the same effect two rounds in a row:  

• The Guard can choose one of the three turrets in the room with it, that turret then targets one creature it can see within 100ft and makes the following attack:
  
Autofire. Ranged Weapon Attack: +10 to hit, range 60/100 ft., one target. Hit: 28 (6d6+10) piercing damage.
• The Guard can cause all 6 Gems in the room to recharge, resetting the charges and negative/positive effects that can be dealt from them. In doing so the Guard regains half its maximum health, then a quarter, then an eighth, and then not be used again.

A large almost square room with rubble and large cylindrical pillars Around the room are 6 large clumps of crystals, which react when certain magic is cast on them. Some have positive effects some have negative effects:

• Purple - Psychic: Stun the Boss for one round (works once)
• Gold - Thunder: Knocks boss prone (works once) lightning: blinds the party for one turn
• White - Radiant: removes the bosses Prismatic Beam ability for 1d4 turns
• Orange - Fire: weakens the boss, so next successful hit counts as a critical (works once) cold: the next attack against the boss if resisted
• Blue - Cold: slows the boss for one turn (works 3 times)
• Black - Necrotic: the next attack against the boss heals half the damage back on the person who landed the attack (works 2 times)