Either left voluntarily or kicked out, who left you shook?
I'd say Jexit had the most cultural impact. Years later fans are still speculating on the bts tea of Taeyeon vs Sica
But Jinni was the most shocking for me. Left everyone gagged.
Some other contenders are:
Park "Korea is Gay" Jaebum
An exit so iconic and shocking it sparked pr3gnancy rumors
Casualties of Korea's bullying #MeToo
Whatever tf was going on with that Woojin guy
Mutliple drug scandals
The exit everyone--apparently even the fans--wanted
The exit literally nobody wanted
+ many many more