Archeoaevis is a boss fought at Ronka Ruins, fought in five parts with the first four having hardly any differences and the last being after it's been defeated and revived. It is a challenging boss as it's highly powerful, using such abilities as Blaze, Thunder, and Maelstrom. It is also capable of changing its elemental weakness with Wall Change.
Archaeoaevis is an enemy fought only at the Zertinan Caverns, in the Balamka Fault area. While being moderately powerful in the original version, it has become highly dangerous in the International version due to its stats being severely changed. It is the only source of the Emperor Scales needed for the Durandal.
The creature's name comes from the Greek suffix archeo- meaning "ancient" and the Latin word avis meaning "bird".