Pokemon Violet - Solo Azumarill defeats 7-star Dondozo raid

Azumarill takes out the Unaware Dondozo with a very special set.

With Unaware, Belly Drum is out of the picture, and so Azumarill actually has to go special to hit Dondozo's lower defense more effectively, as well as actually change to the super-effective Grass tera type and run the 120 BP Grass Knot for maximum damage, and every multiplier counts coming from 60 SpA.

Fortunately Dondozo is light on the scripted actions, so it's pretty safe to get maximum Mud-Slaps to ruin its accuracy and brute force through the fight. Azumarill has other helpful debuffs to debilitate Dondozo's offense and defense, but they mainly just matter before and after the shield, which is a very small part of the battle. Chilling Water might have helped without Intimidate. Since Azumarill doesn't need Huge Power or Sap Sipper here, it can actually run Thick Fat to cover the Ice weakness from going Grass, though boosted Avalanche does about the same as tera Wave Crash anyway.

Arboliva AI is key here to set Grassy Terrain for more damage and healing as well as occasional SpD drops with Earth Power and Energy Ball, and Arcanine intimidates and burns eventually to lower Dondozo's damage output even more if it hits.

Alternatively you can set debuffs early and just wait for the shield to go up on time instead of HP, so the main chunk of the health bar goes down faster before Dondozo resets debuffs at 70% HP.