Annihilating Aura. Any creature that starts its turn within 30 feet of the nightmare takes 21 ( 6d6 ) necrotic damage and grants the nightmare advantage on attack rolls against it until the start of the creature's next turn. Undead are immune to this aura. Eidetic Learning. The nightmare can not be permanently killed so long as typhon organisms infest Luna Castellum. Each time it encounters the same group it will automatically have a single counter to the preys abilities. For example, facing a psi-user that needs sight to use his abilities, the nightmare will gain the blindness/deafness spell as an action. Or if an attacker uses radiant damage it will lose its vulnerability the next encounter and then gain resistance the following on so on. Life Eater. A creature reduced to 0 hit points from damage dealt by the nightmare dies and can't be revived by any means short of a wish spell. Legendary Resistance (1/Day). If the nightmare fails a saving throw, it can choose to succeed instead. Instantaneous Movement. The nightmare can move through other creatures and objects as if they were difficult terrain. It takes 5 ( 1d10 ) force damage if it ends its turn inside an object. Its movement is more akin to a teleport than actual movement so it may pass through hostile creatures and attack from behind. Its movement never provokes attacks of opportunity. Psychic Mirror. If the nightmare takes psychic damage, each creature within 10 feet of the the nightmare takes that damage instead; the nightmare takes none of the damage. In addition, the nightmare’s thoughts and location can’t be discerned by magic. Reactive. The nightmare can take 1 reaction at the end of each enemies turn. Turning Defiance. The nightmare and any other typhon within 30 feet of it have advantage on saving throws against effects that turn Undead. Unusual Nature. The nightmare doesn’t require air, food, drink, or sleep.
Multiattack. The nightmare uses Ephialtes Slash twice, or it uses Ephialtes Slash and Finger of Doom, if available. Vita Exhaurire. Melee Weapon Attack: 1d20+13 to hit, reach 15 ft., one target. Hit: 28 ( 5d8+6 ) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, the target is also blinded and looses 10% of his total XP. The blinded condition and hit point reduction lasts until the target finishes a long rest. The XP loss is permanent. Scream of Doom (Recharge 6). The nightwalker points at one creature it can see within 300 feet of it. The target must succeed on a DC 22 Wisdom saving throw or take 26 ( 4d12 ) necrotic damage and become frightened until the end of the nightmare's next turn. While frightened in this way, the creature is also paralyzed. If a target's saving throw is successful, the target is immune to the nightmare's Scream of Doom for the next 24 hours.
Disrupt Life. As a reaction to being struck, each non-undead creature within 20 feet of the nightmare must make a DC 21 Constitution saving throw against this magic, taking 21 ( 6d6 ) necrotic damage on a failed save, or half as much damage on a successful one.
The nigthmare 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 nightmare regains spent legendary actions at the start of its turn. Frightening Gaze.frightenednightmare
Roll a 1d4 timer and tick the timer down each time the nightmare has a turn. If the timer is on 1 at the start of the nightmare's turn the following effect triggers: Arcane Enchantment. An orb appears on the battlefield of purple light. It shoots a coruscating line from its centre and begins spinning. These orbs persist until the end of the battle. The orbs impose a bane on attack rolls and saving throws. Any creature that fails a saving throw or attack roll takes 5 necrotic damage. Both the bane and the damage is cumulative. The timer has a -1 applied for each arcane enchantment active on the battlefield. A character can dispel a single enchantment using dispel magic or a rogue can disable one with a successful DC 14 Thieves Tool check. On a failure, the rogue takes 5 necrotic damage.
The nightmare can be encountered anywhere on Luna Castellum but only after multiple lesser typhoons have been killed by the party. Wherever it is encountered it will have some loot scattered in its "lair". Treasure should generally be themed to reflect the environment where possible:
Luna Castellum