Thank you for taking the time to read the page. It's good to get feedback on my conworld.
The final fall of the Empire starts during Lokiduer's reign, a century after Maniko. At this point in time the Vreski Empire has become a closed-in society with scant trade beyond its borders. Lokiduer's long reign and failure to marry/produce heirs leads to the rise of competing factions - which sets the scene for the civil war to follow. The end result of the civil war is a massive reduction in the population (death, disease, exodus into the interior of the continent), which in turn leads to the abandonment of many settlements and the collapse of much of the agricultural system - without the necessary food, and no viable links beyond the border to support the existing power structures, the Empire fails.
This scenario has possible precedents on Earth (eg Indus Valley civilisation, golden age of the Mayans, etc), but is - I think - much more reasonable on Kalieda, for 2 key reasons:
1. The planet is generally hostile to terrestrial life due to biological/biochemical differences, making human settlements much more fragile - there's more info about this on the
art and science of cultivation and related biology web page if you have a spare 15 mins.
2. The whole planet is in the midst of a climate shock as temperatures fall and ice caps form at the poles - though the disaster has less of an impact on the lower lattitudes (the Empire straddles the equator), it still has some effect on local climates and cultivations.
Does this help?