The Secrets of Allag™

That phrase is used nearly every time Azys Lla is brought up. Like the Ultima Weapon, Azys Lla is a tangible link to the knowledge of Allag; something you can learn from and use and make their abilities your abilities. Azys Lla was dedicated to the binding and control of primals, eikons, and dragons. This knowledge would well serve a primal-infused aspiring-God-King waging a millennium-long war against dragons, so the Ascians offered it, the same way they offered the Ultima Weapon - the power to rid Eorzea of primals - to Gaius van Baelsr. If the Ascians were trying to corrupt Fat Chocobo, it they would use a fishing rod baited with a slice of cake of a recipe devised by Xande himself.