Over 3,000 years ago, Kalos was in a war. AZ's Pokémon, a Floette, was forcibly recruited and died in the war. But AZ invented a machine both giving eternal life and bring dead back to life. He used it to recover his Floette which gave them both eternal life. However, he still was angry to the people for their greediness so he converted his machine to the ultimate weapon which needs to suck life of many living beings to create a. It destroyed almost every living being in an extremely big perimeter. After that, he crowned himself the new king of Kalos. But his Floette obviously disagreed with the murdering of millions and left him. He realized what he did and spent thousands of years as a wanderer to search it. But in modern ages, Lysandre reused the machine to kill all living beings except Team Flare to prevent overpopulation. He wanted to use the power of Yveltal/Xerneas for the machine to affect the entire world but as the protagonist stopped the process. The weapon worked but was too weak to full use it and due to the evacuation of the city, it didn´t create much damage except it apparently destroyed itself and seemingly killed Lysandre (although it was revealed that he survived in Pokémon Ultra Sun/Ultra Moon).
After the protagonist defeated Diantha, AZ battled the player to find it out how it is to be a trainer. After it, he said that he regretted what he did and his Floette floats from the sky, revealing that it was watching him all the time.
Although not by name, AZ is mentioned several times during the Delta Episode of Pokémon Omega Ruby and Alpha Sapphire. He and his actions 3,000 years ago are first mentioned by Mr. Stone, who tells that his grandfather got the idea to use the same energy used by the ultimate weapon to improve the lives of people and Pokémon alike, thus leading to the creation of Infinity Energy, which the Devon Corporation used to grow into one of the top industries in Hoenn. Later, the player overhears Wallace talking with his master, learning that the tree planted in front of the entrance to the Cave of Origin was given to the people of Sootopolis by a "huge man who visited from the Kalos region." Underneath the tree there is a flower of the same kind as the one carried by AZ's beloved Floette. AZ is mentioned once more by Zinnia at the Sky Pillar, telling that "a tall visitor from a distant land" once witnessed how Mega Rayquaza stopped a fight between Primal Groudon and Kyogre, having said, "It is the Δ (Delta), born of the great disturbances in this world. By the bonds born of mankind's wish and the power of the stones, it will calm the troubles that plague the world."
- AZ is the tallest person in the main series games.
- He did not appear in anime.
- AZ is the oldest known human in the history of Pokémon, games or otherwise.
- All of the Pokémon that AZ uses in battle are Pokémon associated with ancient civilization or longevity; Torkoal is based on a tortoise, which can live for multiple centuries, and both Golurk and Sigilyph are Pokémon thought to be from ancient times. Also, all know Return, indicating a high friendship level with AZ.
- His name is from the letters A and Z, meaning the beginning and end.
- An interview with Junichi Masuda in Game Informer magazine reveals that AZ's Floette was given to him by his late mother and was taken by force by the soldiers fighting in the war.
- The interview also reveals that AZ's great height is due to the influence of the ultimate weapon's power on his body, and that he continued to age despite being immortal.