I have looked into many historical leaders who have, as a defensive tactic, or by the repercussions of their indulgent or careless actions, factored into some downfall of their nation or empire, such as Hitler, Gorbachev, and some of the nastier Roman emperors.
I am, however, not looking for a mythical ruler who caused this downfall by consequence of their actions or personal protection. I want to know if there are any stories of rulers in any mythology, rulers who (preferably) single-handedly built a town/city/empire and decided, after witnessing some malfunction or horrors within the domain, to destroy what they had built and betray the people they had led.
Any variants are appreciated, but I'm looking for specificity here.