Boss Encounter 9 - lvl 5 to 10

1x Djinni Large elemental , chaotic good
Armor Class 17 (Natural Armor) Hit Points 161 (14d10 + 84) Speed 30 ft., fly 90 ft.
STR 21 (+5) DEX 15 (+2) CON 22 (+6) INT 15 (+2) WIS 16 (+3) CHA 20 (+5)
Saving Throws DEX +6, WIS +7, CHA +9 Damage Immunities Lightning, Thunder Senses Darkvision 120 ft., Passive Perception 13 Languages Auran Challenge 11 (7,200 XP) Proficiency Bonus +4
Elemental Demise. If the djinni dies, its body disintegrates into a warm breeze, leaving behind only equipment the djinni was wearing or carrying.
Innate Spellcasting. The djinni's innate spellcasting ability is Charisma (spell save DC 17, +9 to hit with spell attacks). It can innately cast the following spells, requiring no material components:
At will: detect evil and good, detect magic, thunderwave
3/day each: create food and water (can create wine instead of water) , tongues, wind walk
1/day each: conjure elemental (air elemental only), creation, gaseous form, invisibility, major image, plane shift
Actions Multiattack. The djinni makes three scimitar attacks.
Scimitar. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: (2d6 + 5) slashing damage plus (1d6) lightning or thunder damage (djinni's choice).
Create Whirlwind. A 5-foot-radius, 30-foot-tall cylinder of swirling air magically forms on a point the djinni can see within 120 feet of it. The whirlwind lasts as long as the djinni maintains concentration (as if concentrating on a spell). Any creature but the djinni that enters the whirlwind must succeed on a DC 18 Strength saving throw or be restrained by it and take (1d6) damage. The djinni can move the whirlwind up to 60 feet as an action, and creatures restrained by the whirlwind move with it. The whirlwind ends if the djinni loses sight of it.
A creature can use its action to free a creature restrained by the whirlwind, including itself, by succeeding on a DC 18 Strength check. If the check succeeds, the creature is no longer restrained and moves to the nearest space outside the whirlwind.
Summoned Air Elemental Large elemental , neutral
Armor Class 15 Hit Points (12d8 + 24) Speed 0 ft., fly 90 ft. (hover)
STR 14 (+2) DEX 20 (+5) CON 14 (+2) INT 6 (-2) WIS 10 (+0) CHA 6 (-2)
Damage Resistances Lightning, Thunder; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks Damage Immunities Poison Condition Immunities Exhaustion, Grappled, Paralyzed, Petrified, Poisoned, Prone, Restrained, Unconscious Senses Darkvision 60 ft., Passive Perception 10 Languages Auran Challenge 5 (1,800 XP) Proficiency Bonus +3
Air Form. The elemental can enter a hostile creature's space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.
Actions
Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: (2d8 + 5) bludgeoning damage.
Whirlwind (Recharge 4–6). Each creature in the elemental's space must make a DC 13 Strength saving throw. On a failure, a target takes (3d6 + 2) bludgeoning damage and is flung up 20 feet away from the elemental in a random direction and knocked prone. If a thrown target strikes an object, such as a wall or floor, the target takes (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 13 Dexterity saving throw or take the same damage and be knocked prone.
If the saving throw is successful, the target takes half the bludgeoning damage and isn't flung away or knocked prone.