down + fall

source: Anima Game Fan!

a loss of power, prosperity, or status:

〖通例one's/the ～〗 (権力･繁栄などからの)転落, 零落, 没落

e.g. the crisis led to the downfall of the government.

the cause of a downfall:

破滅の原因

e.g. his intractability will prove to be his downfall.