Complex sentence: Manuel, whose pen name was "Membrillo", earned his greatest success playing "Ñico Fernández", a comedic character in Puerto Rican television that represented a Cuban immigrant who constantly used hyperbole to describe his homeland and all things Cuban.
Split into simpler sentences: Manuel, whose pen name was "Membrillo", earned his greatest success playing "Ñico Fernández", a comedic character in Puerto Rican television. This character was a Cuban immigrant with a habit of using hyperbole to describe his homeland and all things Cuban.