懂中文 Dong Chinese

罪魁祸首

zuì​kuí​huò​shǒu

fig. main cause of a disaster

Definitions

罪魁祸首 (罪魁禍首) 

zuì​kuí​huò​shǒu

criminal ringleader, main offender (idiom); main culprit; fig. main cause of a disaster

Sources