哈利·波特最终击败了他一生的宿敌伏地魔。

Harry Potter finally defeated his lifelong ___nemesis, Voldemort.

过度自信最终成为了他的宿敌，导致项目彻底失败。

Overconfidence turned out to be his ___nemesis, causing the project to fail completely.

暴君最终遭遇了他的宿敌，那是上天派来惩罚他的使者。

The tyrant finally met his ___nemesis, the divine agent sent to punish his cruelty.