Fenrir founded a liberal democracy that placed the people above parochial monied interests. He quickly eliminated social scourges such as illiteracy, hunger, and predatory business and gentried pathological self-interests. Not content to let social equity stand, those interests formed evil alliances with external empires, now enemies, who quietly worked to subvert the state system of prosperity that Fenrir had carefully cultivated over many years to help and elevate the people they selflessly served because it seemed noble to them.
The empires were determined to make an example of Fenrir's little model society, poisoning the well so as to demonstrate to the world why sociopathic capitalistic predation is 'always preferable' to equality and collective prosperity. Endlessly, the external forces quietly cultivated evil memes, self-destructive memes, given out with a straight face as if offering children poison candy. While this quickly introduced many form of strife, it alone was not sufficient to bring down Fenrir's equitable land. And so, next, the external empires manipulated the international systems of finance to crash Fenrir's currency, but the people still had heart and each other, and even this couldn't pull the walls down upon them, and they endured in austerity, making art, poetry, culture for each other, celebrating their own noble spirits in dignity.
Finally the external empires just dropped a nuke. It doesn't even matter if it's a real or figurative one, genocidal-like effects took root and destroyed, finally, dogryme6's civilization, its survivors scattered to the four corners. But even then, its memory lived on as legendary, immortal, and eventually, it inspired many more to follow in their paths to build flourishing-on-Earth for all.