expression
fight fire with fire; set a thief to catch a thief
Proverb meaning to use the same harmful means to counter a problem, especially using an evil to defeat another evil.
毒をもって毒を制すという言葉があるように、時には悪い手段で悪を倒すことも必要だ。
As the saying goes, 'fight fire with fire'; sometimes it's necessary to use bad means to defeat evil.
A Japanese calque of the English proverb 'fight fire with fire' or a similar Chinese saying. The exact origin is uncertain, but it is a well-established idiomatic expression.