A4-D was a droid who served as a medic to General Grievous. A4-D was frequently annoyed as he constantly has to fix General Grievous's broken parts, especially when Grievous's legs and extra arms were cut off, and he had a cracked face plate. After giving Grievous an operation, he sent him to battle and watched him via cameras. While he was cheering for his master, he didn't notice his surroundings, and he was decapitated by Kit Fisto.
A4-D's head printing is solely comprised of a sticker.
A4-D is a non-playable character in LEGO Star Wars III: The Clone Wars. In play you can see him in the background repairing Grievous just like in the TV show, while in one cutscene, A4-D offers his master some oil, and when Grievous gags from drinking it, A4-D just chuckled in surprise.