An Aeroape is one of the flying primates created by Professor Cornelius Senear. One of these constructed creatures, and possibly several more like it, ✣ attack Castle Wulfenbach while the Baron is in the Great Hospital of Mechanicsburg recovering from the injuries he received when one of Agatha's Wagon Clanks, Baba Yaga, ✣ fell on him during the Battle of Sturmhalten.
The Wulfenbach empire's accompanying Siege of Mechanicsburg draws in clanks, artillery and airships from countless opportunistic Europan Sparks and power-players, among them Professor Senear, who, apparently, is an old acquaintance/enemy/nuisance of the Baron.
Based on remarks from Wulfenbach personnel during the attack, there are presumably much smaller versions of Aeroapes, and for them to reach this size is especially noteworthy, pointing towards the possible specialty of Professor Senear.
Following the attack on Castle Wulfenbach, which is evidently repelled off-screen in particularly emphatic fashion, Professor Senear seeks asylum ✣ in Mechanicsburg for himself and his surviving Apes.
The Novels[]
Agatha H. and the Siege of Mechanicsburg remarks in a footnote that even by Sparkish standards Professor Senear is/was indeed obsessed with creating Aeroapes, and succeeded to the point that colonies of the creatures now inhabit city rooftops throughout Europa.
Possibly relevant outside information[]
The Foglios may or may not have been influenced by L. Frank Baum's winged monkeys and/or this classic Silver Age Comics Story.