By Alan McCoy from Dungeons & Dragons: Fundamentals
How to build challenging encounters against an Air Elemental
Note: This has been prepared utilizing only the 5E Core Rules. The Air Elemental can be found in the Monster Manual page 124.
Air Elementals are summoned, not evolved creatures, as such they have no specific form, they can be bound into a shape by the will of their summoner or creator. When speaking of Air Elementals, these terms can be used interchangeably. When summoned without a specific shape requirement, they tend to take a shape that fits their nature such as a funneling cloud with the vague outline of a face.
An Air Elemental cannot be summoned in an area unless there is a significant volume of Air present.
Step 1) Let’s review what we know about the Air Elemental
Air Elementals extremely nimble and well above average in strength and toughness. They have very little in the way of personality and intelligence.
Air Elementals fly amazingly fast (90 feet/round) thus difficult terrain will not slow them. They can also hover. They can move through an opening a mere one inch in diameter without slowing. They can also enter a hostile creature’s space and stop there.
Air Elementals take half damage from lightning, thunder and non-magical bludgeoning, piercing and slashing attacks. They are also completely immune to poison.
Air Elementals are conditionally immune to Exhaustion, Grappled, Paralyzed, Petrified, Poisoned, Prone, Restrained and Unconscious. They do not need to consume (eat or drink), breathe or sleep.
Air Elementals can form a whirlwind, a cyclone with which to buffet and toss about enemies. The Air Elemental is a size large creature and the whirlwind can affect multiple enemies.
Air Elemental senses include Darkvision 60 feet, they have a passive perception of 10.
Step 2) Determine the probable Strategy
Air Elementals are constructs that exist only to serve their creator. They do come with certain default combat techniques built in that serve much like the instincts of an animal. Their low intelligence makes it hard for them to change tactics, thus they will often continue even a losing strategy unless directed to do something else by their creator.These elementals maintain a telepathic link to their creator if that creator remains within 120 feet. The creator can receive the sensory input of the elemental.
Step 3) Determine Tactics
The primary attack is of course their multi-attack slam, using the wind and or available debris to bash their target into submission.
With their Whirlwind ability the Air Elemental can enter the space of a hostile creature and begin, buffeting their target with debris and flinging them twenty feet and knocked prone, if they hit an object that stops their progress, they take even more damage.
Additionally, these powerful creatures have a few programed techniques available to them.
Technique #1: The Shove – The Elemental can sacrifice one of its slam attacks to blow an opponent back five feet. It will do this if the target is near the edge of a drop-off or otherwise could be endangered.
Technique #2: The Grapple – The Elemental can grab a target and carry it aloft, then drop it allowing it to take falling damage.
Technique #3: The Balloon – The Elemental can fill the lungs of an air breathing creature, preventing them from speaking or even exhaling.
Technique #4: The Howl – The Elemental can cause its winds to howl, making it impossible to hear anything else.