After being turned into a cyborg by Count Dooku before the Clone Wars, Grievous developed a slight cough due to his few remaining organs not taking well to his cybernetic implants.
Unfortunately however, this cough was made much, much worse at the battle of Coruscant, when Grievous’s plating was force crushed by Mace Windu, further aggravating his horrid cough and making it almost unbearable. This cough would remain with Grievous for the rest of his life… which was not very long.
Why Does General Grievous has his signature cough?
