Phased Boss Fights

One concept that video-games do well Phased Boss fights, where the encounter has a several stages that players work through to defeat the boss.  The DMG goes into this a little bit in the multipart encounter section, talking about monsters that fight in waves.  This is different as it can be one creature, but the concept is similar.  Here are some rules to spice up a Boss Monster encounter inspired by our favorite video games.

Phased Boss Monster Rules

  • When a Phased Boss Monster begins a new phase, it essentially becomes a new creature. The monster keeps its place in the initiative order. Any further damage taken does not carry over to the new phase.
  • When a Boss Monster gets to 0 hit points, it can transition to a new phase, if there is one available.
  • As the Boss Monster transitions to a new phase, if it had any lair or legendary actions, it stops using them until it begins its next turn, if available.
  • When a Boss Monster begins a new phase, it is considered a new creature. Thus abilities or spells with a continuing effect will end, such as Witchbolt, the slowing effect from Chill Touch, or the advantage granted to the next attacker by Distracting Strike.
  • Try to warn a player that’s about to use a once-per-day ability or high level spell on a Boss Monster that is transitioning to the next phase. They might get upset if they end up wasting their resources when the new phase wipes away any extra damage or debuffs.
  • I recommend stopping combat during the phase transition and use the time to describe what is happening. Think of it like a video game cut sequence and the players cannot interrupt it. Combat then resumes with the creatures new turn. If anybody remaining in the initiative order wants to do something as the Phase transitions, allow them a turn to reposition or cast a spell (with a reminder that any damage or debuffs will not carry over to the new phase).
  • The rules for Experience Points for a Phased Boss Fight are the same as a Multipart encounter.

Example Encounter

For our example encounter I will using Orlog the Cruel.  This encounter is designed for a 4th (hard fight) or 5th (normal battle) level party.  The party will have to be clever and use resources wisely, as Orlog is a 3 part encounter.

History of Orlog

Three hundred years ago, the Oni only known as the Hungering Darkness led the ancestors of Orlog’s tribe. Those were better times, for instead of having to eat Goblins, Orlog’s ancestors ate Humans from a close by kingdom. This, of course, attracted adventurers, which was ultimately the Oni’s undoing. However, during that final battle, the Hungering Darkness fled into the cavern, where the adventurers ultimately killed him. Orlog’s ancestors never found the body and believed that the Hungering Darkness had ascended, so the tribe now glorifies him as a God. Because of this worship, the Hungering Darkness’s spirit merged with his gear. Once Orlog found it, the Oni’s spirit fused into his own. Now Orlog the Cruel is being slowly consumed by the Hungering Darkness, which has allowed the “lucky” Ogre to take the position of tribal chieftain and push once again into the human lands.

Hungering Darkness Item Set

Orlog has attuned to a powerful item set. (Do You Want to Know More?) This set is Large sized, so most players shouldn’t be able to wear it. Plus, it has the powerful corrupting spirit of a dead Oni inside it. DMs may allow the players to use the steel of the Glaive to make a new weapon, or use the bits of the chainmail to craft new armor, but that is always up to you. Reforging the items will break the set abilities however, so at best you could make a +1 weapon and a cloak of protection.

Black Glaive the weapon of the Oni. Due to the evil spirit residing in this, it is now a +1 weapon and when wearing the full set, it does an additional 1d6 Necrotic Damage.

Cloak of Darkness This cloak functions as a cloak of protection +1. If the wearer is attuned to another item in the set, it grants advantage on perception checks.

Blacked Chainmail This armor is a normal set of Ogre-sized chainmail. However it is blackened by the fireball spell that ultimately killed the Hungering Darkness. If attuned to all three items in the set, it grants the wearer an Oni’s ability to regenerate. The wearer regains 10 hit points at the start of its turn if it has at least 1 hit point.

Phase 1

When first encountered Orlog appears to be nothing more than an Ogre wearing an unusual set of armor. However, close inspection shows that his eyes have a dim blue glow, and it is unusually cold around him.

Skill Checks
Intelligence (Arcane) DC 10  Orlog is wearing a set of magical items.
Intelligence (History) DC 10 Orlog is known for his luck.
Intelligence (History) DC 15 Orlog’s weapon is the same weapon wielded by a powerful Oni who led the local Ogres three hundred years ago.
Intelligence (Religion) DC 10  The cold is a sign that there is a restless spirit around Orlog.

Orlog the Cruel
Large Giant, Chaotic Evil
AC 17 (Chain Mail and Cloak of Protection)
Hit Points 59 (7d10+21)
Speed 40ft
Str 19 (+4), Dex 8 (-1), Con 16 (+3), Int 5 (-3), Wis 7 (-2), Cha 7 (-2)
Senses Darkvision 60 feet, Passive Perception 8
Languages Common, Giant
Special Orlog has +1 to all saves due to his Cloak of Protection
Challenge 3 (700xp)

Regeneration – Orlog regains 10 hit points at the start of its turn if it has at least 1 hit point.

Legendary Resistance (1/Day). Orlog is extraordinarily lucky. If he fails a saving throw, Orlog can choose to succeed instead. He can only use this ability once until he completes a long rest.

Black Glaive. Melee Weapon Attack: +7 to hit, reach 10 ft, one target. Hit 16 (2d10+5) piercing damage plus an additional 4 (1d6) Necrotic Damage.

Javelin. Melee or Ranged Weapon Attack: +6 to hit, reach 5 ft or 30/120 ft. One target. Hit 11 (2d6+4) piercing damage.

Phase 2

The Hungering Darkness is enraged that its host was killed. The power of this rage manifests itself in the physical realm as a black liquid that leaks from Orlog’s body after his death, and there is a sudden shift in temperature, making the room even colder. On Orlog’s next turn, the protoplasm flows into the item set and animates it.

Skill Checks
Intelligence (Religion) DC 10 – the Black Liquid is ectoplasm.
Intelligence (Religion) DC 15 – Black ectoplasm is produced by an unusually wrathful spirit.

Rage of the Hungering Darkness
Large Undead, Chaotic Evil
AC 17 (Chain Mail and Cloak of Protection)
HP 39 (6d10 + 6)
Speed 25ft
Str 14 (+2), Dex 11 (+0), Con 13 (+1), Int 14 (+2), Wis 8 (-1), Cha 15 (+2)
Damage Resistances Bludgeoning, piercing and slashing from nonmagical weapons.
Damage Immunities Poison
Condition Immunities Blinded, charmed, deafened, exhaustion, frightened, paralyzed, petrified, poisoned.
Senses Blindsight 60ft (blind beyond this radius), passive perception
Languages Giant, Common
Special: +1 to all saving throws due to the cloak of protection
Challenge 3 (700xp)

Regeneration Rage of the Hungering Darkness regains 10 hit points at the start of its turn if it has at least 1 hit point.

Black Glaive Melee Weapon Attack +5 to hit, reach 10 ft, one target. Hit 14 (2d10+3) piercing damage, plus an additional 4 (1d6) Necrotic Damage.

Phase 3

Once players deal enough damage to the Rage of the Hungering Darkness, the ectoplasm animating the item set cannot maintain enough strength to lift the items. All the items come crashing to the floor, and the liquid oozes back into the body of Orlog, dragging the Glaive behind it. Suddenly the eyes of the Ogre open with an unearthly blue light.

Skill Checks
Intelligence (Arcane or Religion) DC 10 – The body is animated by magic and has created an ogre zombie.

Orlog the Ogre Zombie
Large Undead, neutral evil
AC 8
Hit Points 85 (9d10 +36)
Speed 30ft
Str 19 (+4), Dex 6 (-2), Con 18 (+4), Int 3 (-4), Wis 6 (-2), Cha 5 (-3)
Saving Throws Wis +0
Damage Immunities Poison
Condition Immunities Poisoned
Senses Darkvision 60ft, Passive 8
Languages Understands Giant and Common
Challenge 2 (450xp)

Undead Fortitude. If damage reduces Orlog to 0 hit points, it must make a Constitution saving throw with a DC of 5+ the damage taken, unless the damage is radiant or from a critical hit. On a success, Orlog drops to 1 hit point instead.


Black Glaive Melee Weapon Attack +7 to hit, reach 10 ft, one target. Hit 16 (2d10+5) piercing damage plus an additional 4 (1d6) Necrotic Damage.


Once players drop the animated zombie of Orlog, the spirit of the Hungering Darkness loses all its power. The black ectoplasm leaks from the zombie’s body, turning into a mist that almost seems to scream as it fades away. However, unless the players take the time to destroy the items that tie the Hungering Darkness to the world, his spirit will linger, waiting for another large size creature to find his gear. A character DC 10 Intelligence (Religion) check to learn this information. Destroying the items is not any more difficult than destroying any normal magic item. If your players are fans of the show Supernatural, you might allow them to burn the item set in salt instead. Players divide 1850xp (modified by the multi part encounter rules in the DMs Guide) among themselves for defeating this threat.

Designer Notes

Orlog uses the stats of a regular Ogre with the added the item set properties. I gave him the legendary resistance because I wrote the bit about him being lucky. Because of his increased AC, raising his challenge rating was appropriate. The Rage of the Lingering Darkness is a mishmash of Animated Armor and Ghost entries. I gave it resistance to nonmagical weapons to keep the encounter interesting, and give a Phase for the casters to shine. Phase 3 just uses that stats of the Zombie Ogre, with the upgraded weapon.

I revisited this concept during our Winter Series, with the Frozen King of the Mountain.

Cthulhu Mythos - Available Now @