Large Celestial, Lawful Neutral
Armor Class 17 Initiative +12 (22) Hit Points 199 (19d10 + 95) Speed 40 ft., Fly 60 ft.
Saving Throws Str +6, Dex +6, Con +11, Int +9, Wis +12, Cha +4
Skills Arcana +9, Perception +12, Religion +15
Damage Resistances Necrotic, Radiant
Damage Immunities Psychic; Charmed, Frightened
Senses Truesight 120 ft.; Passive Perception 22
Languages Celestial, Common
Challenge Rating 17
No magic can observe the sphinx remotely or detect its thoughts without its permission. Wisdom (Insight) checks made to ascertain its intentions or sincerity are made with Disadvantage.
If the sphinx fails a saving throw, it can choose to succeed instead.
The sphinx makes two Claw attacks and uses Roar.
Melee Attack Roll: +12, reach 5 ft. Hit: 20 (4d6 + 6) Slashing damage.
The sphinx emits a magical roar. Whenever it roars, the roar has a different effect, as detailed below (the sequence resets when it takes a Long Rest):
Wisdom Saving Throw: DC 20, each enemy in a 500-foot Emanation originating from the sphinx. Failure: The target has the Frightened condition for 1 minute.
Wisdom Saving Throw: DC 20, each enemy in a 500-foot Emanation originating from the sphinx. Failure: The target has the Paralyzed condition, and it repeats the save at the end of each of its turns, ending the effect on itself on a success. After 1 minute, it succeeds automatically.
Constitution Saving Throw: DC 20, each enemy in a 500-foot Emanation originating from the sphinx. Failure: 44 (8d10) Thunder damage, and the target has the Prone condition. Success: Half damage only.
The sphinx casts one of the following spells, requiring no Material components and using Wisdom as the spellcasting ability (spell save DC 20):
At Will: Detect Evil and Good, Thaumaturgy
1/Day Each: Detect Magic, Dispel Magic, Greater Restoration, Heroes' Feast, Zone of Truth
Legendary Action Uses: 3 (4 in Lair). Immediately after another creature's turn, the sphinx can expend a use to take one of the following actions. The sphinx regains all expended uses at the start of each of its turns.
The sphinx can teleport up to 30 feet to an unoccupied space it can see, and it makes one Claw attack.
Constitution Saving Throw: DC 16, one creature the sphinx can see within 120 feet. Failure: The target gains 1 Exhaustion level. While the target has any Exhaustion levels, it appears 3d10 years older. Failure or Success: The sphinx can't take this action again until the start of its next turn.