While this guide provides a strategy based on typical gameplay elements and mechanics known up to my last update, always be prepared to adapt your tactics based on your character's build and any unique gameplay changes Blizzard might have introduced.
How to Defeat Airidah Keeper of the Dead in Diablo 4
Here's how you can approach defeating Airidah, Keeper of the Dead, in Diablo 4:
Location:
•Airidah is encountered during the "Apex of Misery" quest in Act II, found at the top of Solitude in the Wailing Hills area of Scosglen.
Preparation:
•Level: Ensure your character is adequately leveled, ideally in the mid-teens or higher for a smoother experience.
•Gear: Upgrade your gear at the Blacksmith, enhance your potions at the Alchemist, and consider crafting an Elixir of Lightning Resistance for additional help against her lightning attacks.
•Jewels and Aspects: Equip gear with beneficial aspects, especially those providing resistance or damage reduction.
Fight Mechanics:
Lightning Strikes:
•Airidah summons lightning across the battlefield. Look for indicators on the ground to dodge these strikes.
Mist Form:
•She can turn into mist to relocate. Keep track of where she reappears to continue your attack.
Whirlwinds/Tornadoes:
•These are telegraphed but can be hard to spot. They push you back and deal significant damage. Use abilities that make you invulnerable to dash through or avoid them.
Wraiths:
•At health thresholds, she summons Wraiths. These make her invulnerable until they are destroyed. Focus on killing these quickly.
Strategy: 
•Constant Movement: Keep moving to avoid lightning and tornadoes. The battlefield is large for this reason.
Attack Phases:
•Phase 1: Chase Airidah while dodging her attacks. Attack when she's casting or after dodging a whirlwind.
•Wraith Phases: When she summons Wraiths, destroy them as fast as possible to remove her invulnerability shield. Use this time to heal if necessary.
•Final Phases: She'll continue with increased frequency of previous attacks. Maintain your movement and attack pattern, using your most damaging abilities when safe.
•Use of Environment: While there's no specific mention of using the environment in the provided data, generally, in such fights, pillars or other battlefield elements can be used to block or dodge attacks.
•Healing and Potions: Manage your health potions wisely. Use them when you're out of the protective bubble during her sea of blood attack or when you've taken damage from unavoidable attacks.
After Defeat:
•Loot and Dialogue: After defeating Airidah, engage in dialogue with her before she dies to gain information and loot, which might include unique items or significant gear upgrades.
General Tips: 
•Class Abilities: Utilize class-specific abilities that offer invulnerability or high mobility to navigate the fight better.
•Patience: This fight might require patience due to her teleportation and invulnerability phases.
