Yogg-Saron

[Composer99]

I'm pretty confident when dealing with player character features, but monsters? Not so much.

For kicks and giggles, I've statted up Yogg-Saron. I've tried to make the encounter feel as much like the WoW raid encounter as I could, but as I'm writing this in, I feel like there is one big problem, which is how the tentacles work. In the WoW raid, tentacles spawn as mobs around the encounter, but from a narrative perspective, I feel like these would be Yogg-Saron's tentacles themselves, so the mechanics of their appearance may not really work all that well? It might make more sense for its tentacles to be part of a multiattack action.

Yogg-Saron is meant to be an endgame encounter. However, Yogg-Saron isn't necessarily supposed to be a CR 30 monster itself: a lot of its damage output comes from the tentacles and Guardians it spawns. That said, it should be a high-CR monster, and its proficiency bonus of +8 reflects that.

Anyway, here goes:

Yogg-Saron
Huge aberration (Old God), neutral evil

Armour Class 19 (natural armour)
Hit Points 595 (20d12 + 140)
Speed 0 ft.



STR
DEX
CON
INT
WIS
CHA


19 (+4)
8 (-1)
14 (+2)
21 (+5)
19 (+4)
27 (+8)



Saving Throws Constitution +10, Wisdom +12, Charisma +16
Skills Arcana +13, Deception +16, History +13, Insight +12, Intimidation +16, Perception +12
Damage Resistances poison; bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities necrotic, psychic
Condition Immunities blinded, charmed, deafened, frightened, poisoned, stunned, unconscious
Senses Tremorsense 1 mile, darkvision 240 ft., truesight 120 ft., passive Perception 22
Languages Abyssal, Common, Deep Speech, Infernal, telepathy 120 ft.
Challenge ??

Immobility. Yogg-Saron rests in a pool of liquid saronite and does not move. Yogg-Saron automatically fails any Dexterity ability check or saving throw.

Innate Spellcasting. Yogg-Saron's spellcasting ability is Charisma (spell save DC 26), and it can innately cast the following spells, requiring no components:
At-Will: confusion, darkness, dissonant whispers, dream, ray of enfeeblement
3/day each: banishment, counterspell, fear
1/day each: dominate monster, hold monster

Legendary Resistance (5/day). If Yogg-Saron fails a saving throw, it can choose to succeed instead.

Magic Resistance. Yogg-Saron has advantage on saving throws against spells and other magical effects.

Regeneration. Yogg-Saron regains 20 hit points at the start of any of its turns in which it has at least 1 hit point remaining.

Sanity. Whenever a creature within Yogg-Saron's sight that is hostile to Yogg-Saron rolls initiative, it gains a Sanity score equal to its current Wisdom score. Several of Yogg-Saron's abilities can reduce the Sanity scores of creatures hostile to it. Any creature whose Sanity score is reduced to 0 becomes controlled by Yogg-Saron as if by the dominate monster spell. A creature loses its Sanity score when either it or Yogg-Saron is dead, or 1 minute after it has passed out of Yogg-Saron's line of sight. A creature that has become controlled by Yogg-Saron by means of this feature remains controlled until remove curse or similar magic is used to break Yogg-Saron's control.

Actions
Bite. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 22 (4d8 + 4) piercing damage, and if the target is Large size or smaller, it must succeed on a DC 14 Strength saving throw or become grappled by Yogg-Saron (escape DC 14). Until the target is devoured or escapes the grapple, Yogg-Saron cannot use this action.

Empowering Shadows. Creatures friendly to Yogg-Saron within 30 feet of it gain its regeneration feature for 1 minute.

Extinguish (Recharge after Long Rest). If Yogg-Saron has 60 or fewer hit points at the start of its turn after its Regeneration feature takes effect, it can use this action. Each creature within 60 feet of Yogg-Saron must make a DC 18 Constitution saving throw. A creature that fails its save is reduced to 0 hit points. A creature that succeeds its save takes 16 (3d10) necrotic damage. Tentacles, Guardians of Yogg-Saron, undead and constructs are not affected.

In the Mind's Eye (Recharge 6). Ranged Spell Attack: +16 to hit, range 120 ft., one target. Hit: 5 (1d10) psychic damage and the target is banished to a demiplane for 1 minute or until it escapes. A creature trapped in this demiplane can use its action to escape by succeeding on a DC 18 Intelligence check. Once the creature leaves the demiplane, it returns to its space, or to the nearest unoccupied space. If it returns at the end of the effect's duration, it loses 1d6 Sanity.

Lunatic Gaze. Ranged Spell Attack: +16 to hit, range 120 ft., one target. Hit: 30 (4d10 + 8) psychic damage and the target loses 1d4 Sanity. This damage ignores resistance or immunity to psychic damage.

Spawn Tentacles (Recharge 6). Yogg-Saron conjures 1 corruptor tentacle, 1 crusher tentacle, 1 constrictor tentacle, and one tentacle of its choice from those three options in unoccupied spaces within 120 feet.

Summon Guardians (Recharge 5-6). Yogg-Saron conjures 1d2 Guardians of Yogg-Saron that appear in unoccupied spaces that it can see within 120 feet. If Yogg-Saron's current hit points are less than three quarters of its hit point maximum, it conjures 1d4 Guardians instead. If Yogg-Saron's current hit points are less than half its hit point maximum, it conjures 1d2 Immortal Guardians of Yogg-Saron instead. If Yogg-Saron's current hit points are less than one quarter of its hit point maximum, it conjures 1d4 Immortal Guardians instead.

Bonus Actions

Cast a Spell. Yogg-Saron can cast a spell it knows from its Innate Spellcasting trait that has a casting time of 1 action.

Devour. Yogg-Saron devours a creature grappled by its bite attack. A devoured creature is blinded and restrained, has total cover against attacks and other effects outside Yogg-Saron, and takes 21 (6d6) acid damage and 7 (2d6) necrotic damage at the start of each of Yogg-Saron's turns. If Yogg-Saron takes 30 or more damage on a single turn from a creature inside it, it must succeed on a DC 21 Constitution saving throw or immediately regurtitate all devoured creatures, which fall prone in unoccupied spaces within 10 feet of Yogg-Saron. If Yogg-Saron dies, a swallowed creature is no longer restrained by it and can escape by using 10 feet of movement, emerging prone in an unoccupied space within 5 feet of Yogg-Saron.

Legendary Actions
Yogg-Saron can take 3 legendary actions, choosing from the list below:

Bite: Yogg-Saron makes a bite attack.
Devour: Yogg-Saron devours a creature grappled by its bite attack.
Spawn Tentacle: Yogg-Saron spawns 1 tentacle, which can be a corruptor tentacle, crusher tentacle, or constrictor tentacle, in an unoccupied space within 120 feet.
Summon Guardian (costs 2 actions): Yogg-Saron conjures one Guardian of Yogg-Saron in an unoccupied space that it can see within 120 feet. If Yogg-Saron's current hit points are less than half its hit point maximum, it conjures an Immortal Guardian of Yogg-Saron instead.

[Composer99]

Here are the tentacles.

Corrupter Tentacle
Medium aberration, unaligned

Armour Class 15 (natural armour)
Hit Points 32 (5d8 + 10)
Speed 0 ft.




STR
DEX
CON
INT
WIS
CHA


13 (+1)
11 (+0)
14 (+2)
1 (-5)
1 (-5)
17 (+3)



Saving Throws Constitution +4
Damage Resistances poison
Damage Immunities necrotic, psychic
Condition Immunities charmed, frightened, unconscious
Senses blindsight 60 ft., tremorsense 120 ft., passive Perception 5
Languages --
Challenge Rating 2

Eyeless. The corrupter tentacle is blinded outside the range of its blindsight.

Immobile. The corrupter tentacle does not move, and automatically fails any Dexterity ability check or saving throw.

Innate Spellcasting. Corrupter tentacle's spellcasting ability is Charisma (spell save DC 13), and it can innately cast the following spells, requiring no components:



At-Will: dissonant whispers
1/Day Each: confusion, slow


Mindless. The corrupter tentacle can't be affected by any spell or other effect requiring an Intelligence, Wisdom, or Charisma saving throw.

Actions
Curse of Doom (Recharge 5-6). Ranged Spell Attack: +5 to hit, range 60 ft., one target. Hit: 21 (4d8 + 3) necrotic damage, and the target must succeed on a DC 13 Constitution saving throw or take 9 (2d8) necrotic damage at the start of each of its turns for 1 minute or until the effect is removed by dispel magic, remove curse, or similar magic.

Draining (Recharge 5-6). The corrupter tentacle chooses a single creature within 60 feet that it can perceive with its blindsight. The target must make a DC 13 Constitution saving throw or take 3 (1d6) necrotic damage and be unable to cast spells or activate magic items until the end of the tentacle's next turn.

Plague (Recharge 6). Ranged Spell Attack: +5 to hit, range 60 ft., one target. Hit: 12 (2d8 + 3) necrotic damage and the target is afflicted with a random disease chosen from the options available in the contagion spell.

Pseudopod. Melee Weapon Attack: +3 to hit, reach 10 ft., one target. Hit: 10 (2d8 + 1) bludgeoning damage.


Crusher Tentacle
Medium aberration, unaligned

Armour Class 15 (natural armour)
Hit Points 37 (5d8 + 15)
Speed 0 ft.




STR
DEX
CON
INT
WIS
CHA


19 (+4)
14 (+2)
17 (+3)
1 (-5)
1 (-5)
1 (-5)



Saving Throws Strength +6, Constitution +5
Damage Resistances poison
Damage Immunities necrotic, psychic
Condition Immunities charmed, frightened, unconscious
Senses blindsight 60 ft., tremorsense 120 ft., passive Perception 5
Languages --
Challenge Rating 2

Eyeless. The crusher tentacle is blinded outside the range of its blindsight.

Immobile. The crusher tentacle does not move, and automatically fails any Dexterity ability check or saving throw.


Mindless. The crusher tentacle can't be affected by any spell or other effect requiring an Intelligence, Wisdom, or Charisma saving throw.

Actions
Diminish Power (Recharge 5-6). A creature within 60 feet of the crusher tentacle that it can perceive with its blindsight must make a DC 13 Constitution saving throw. On a failed save, the target takes 13 (3d6 + 3) psychic damage and deals half damage with all attacks and spells for 1 minute, or until the effect is removed with dispel magic, remove curse, or similar magic.

Pseudopod. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 17 (3d8 + 4) bludgeoning damage.

Reactions

Focused Anger (Recharge 5-6). After it takes damage, the tentacle can use its reaction to become affected as if by the haste spell until the end of its next turn. While so affected, the tentacle's pseudopod attacks deal an extra 2 damage. The tentacle does not become lethargic at the end of the effect.



Constrictor Tentacle
Medium aberration, unaligned

Armour Class 15 (natural armour)
Hit Points 51 (6d8 + 24)
Speed 0 ft.




STR
DEX
CON
INT
WIS
CHA


17 (+3)
12 (+1)
19 (+4)
1 (-5)
1 (-5)
1 (-5)



Saving Throws Strength +5, Constitution +6
Damage Resistances poison
Damage Immunities necrotic, psychic
Condition Immunities charmed, frightened, unconscious
Senses blindsight 60 ft., tremorsense 120 ft., passive Perception 5
Languages --
Challenge Rating 2

Eyeless. The constrictor tentacle is blinded outside the range of its blindsight.

Immobile. The constrictor tentacle does not move, and automatically fails any Dexterity ability check or saving throw.


Mindless. The constrictor tentacle can't be affected by any spell or other effect requiring an Intelligence, Wisdom, or Charisma saving throw.

Actions
Multiattack. The constrictor tentacle makes two pseudopod attacks, or one pseudopod and one squeeze attack.

Pseudopod. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 16 (3d8 + 3) bludgeoning damage, and, as long as the tentacle is not currently grappling a creature, the target must succeed on its choice of a DC 15 Strength (Athletics) or Dexterity (Acrobatics) check or become grappled by the tentacle (escape DC 15).

Squeeze. A creature grappled by the tentacle takes 21 (4d8 + 3) bludgeoning damage.

[Composer99]

Here are the Guardians.

Guardian of Yogg-Saron
Medium aberration, neutral evil

Armour Class 13 (natural armour)
Hit Points 52 (7d10 + 14)
Speed 40 ft.



STR

DEX

CON

INT

WIS

CHA



19 (+4)
8 (-1)
14 (+2)
11 (+0)
12 (+1)
17 (+3)



Saving Throws Constitution +4
Damage Resistances poison
Damage Immunities necrotic, psychic
Condition Immunities unconscious
Senses darkvision 120 ft., blindsight 30 ft., passive Perception 11
Languages Deep Speech
Challenge 3

Deathly Ties. A Guardian within 120 feet of Yogg-Saron instantly dies when Yogg-Saron dies.

Shadow Nova. When a Guardian is reduced to 0 hit points or killed outright, it explodes. The guardian is destroyed, and any creature within 15 feet of it must make a DC 12 Constitution saving throw, taking 13 (2d12) necrotic damage on a failed save, or half as much damage on a successful one.

Actions

Multiattack. The Guardian of Yogg-Saron makes three pseudopod attacks.

Dark Volley (Recharge 5-6). Any creature of the Guardian's choice within 60 feet of it must succeed on a DC 13 Dexterity saving throw or take 3 (1d6) necrotic damage. Any creature that takes damage as a result of this effect regains half as many hit points whenever subject to an effect allowing it to regain hit points for 1 minute or until the effect is removed by dispel magic, remove curse, or similar magic.

Pseudopod. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 17 (3d8 + 4) bludgeoning damage.


Immortal Guardian of Yogg-Saron
Medium aberration, neutral evil

Armour Class 15 (natural armour)
Hit Points 85 (10d10 + 30)
Speed 40 ft.



STR

DEX

CON

INT

WIS

CHA



19 (+4)
13 (+1)
17 (+3)
11 (+0)
12 (+1)
17 (+3)



Saving Throws Constitution +6
Damage Resistances poison
Damage Immunities necrotic, psychic
Condition Immunities unconscious
Senses darkvision 120 ft., blindsight 30 ft., passive Perception 14
Languages Deep Speech
Challenge 5

Deathless. An Immortal Guardian cannot be reduced to 0 hit points or killed outright as long as it is within 120 feet of a living Yogg-Saron. Whenever it would be reduced to 0 hit points or killed outright, it is reduced to 1 hit point instead, and any creature within 15 feet of it must make a DC 14 Constitution saving throw, taking 13 (2d12) necrotic damage on a failed save, or half as much damage on a successful save. In addition, the Immortal Guardian must succeed on a DC 15 Constitution saving throw or be stunned until the end of its next turn.

Deathly Ties. An Immortal Guardian within 120 feet of Yogg-Saron instantly dies when Yogg-Saron dies.

Empowered. While an Immortal Guardian is under the effect of Yogg-Saron's Empowering Shadows, it is affected as if by the haste spell. It does not become lethargic at the end of this effect.

Shadow Nova. When an Immortal Guardian is reduced to 0 hit points or killed outright, it explodes. The guardian is destroyed, and any creature within 15 feet of it must make a DC 14 Constitution saving throw, taking 13 (2d12) necrotic damage on a failed save, or half as much damage on a successful one.

Actions

Multiattack. The Immortal Guardian of Yogg-Saron makes three pseudopod attacks.

Dark Volley (Recharge 5-6). Any creature of the Immortal Guardian's choice within 60 feet of it must succeed on a DC 13 Dexterity saving throw or take 3 (1d6) necrotic damage. Any creature that takes damage as a result of this effect regains half as many hit points whenever subject to an effect allowing it to regain hit points for 1 minute or until the effect is removed by dispel magic, remove curse, or similar magic.

Pseudopod. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 17 (3d8 + 4) bludgeoning damage.

Shadow Drain. Ranged Spell Attack: +6 to hit, range 60 ft., one target. Hit: 19 (3d10 + 3) necrotic damage, and the Immortal Guardian regains a number of hit points equal to the damage inflicted.