Any damage done to Altaria ex by attacks from Stage 2 Evolved Pokémon (both yours and your opponent's) is reduced by 30 (after applying Weakness and Resistance).
Dive スピードひこう
20
Dragon Mist ドラゴンミスト
70
This attack's damage isn't affected by Resistance, Poké-Powers, Poké-Bodies, or any other effects on the Defending Pokémon.
Release information
Both Altaria ex and Swablu were pulled forward from their Japanese release, June 2005's Mirage Forest, being first released in the English EX Emerald expansion in May 2005.
Trivia
Origin
Mist is a move in the Pokémon games that Altaria can learn. Dive is also a move in the games; however, Altaria cannot learn it and its Japanese name is not the same as the attack in the games, making the move and this attack unrelated. This particular attack first appeared on Brock's Golbat from Gym Heroes.