system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] What happened to General Grevious?

Why is he a cyborg? What happened to his original body?
gpt
Canon: Grevious was a warrior who slowly started replacing his body parts with cyborg parts eventually becoming a full on cyborg. 

Legends: Dooku had Grevious's ship destroyed barely leaving him alive and dooku turned him into a cyborg.