Evidently the commander of “Autobot City” in the Transformers animated movie, Ultra Magnus takes up the Autobot leadership after Optimus Prime falls in battle. His term as leader is short-lived, however, as he himself is killed by Galvatron shortly afterwards. However, his death is even more short-lived, as he’s almost immediately reconstructed by the helpful natives of the Planet of Junk.
This leads to a lot of questions related to fatalities in Transformers, especially regarding the cartoon movie which saw the death of many, many Transformers, both Decepticon and Autobot. If Transformers can just be put back together, like damaged machines (which, when you get right down to it, they are), why don’t most of the 20erous “fatalities” from the movie come back? Too lazy to screw back together the parts of your fallen comrades? This might almost be a possibility with the evil Decepticons, where death of a superior means promotion, but what excuse do the law-abiding Autobots have?
Why, toy sales, of course! Since Ultra Magnus was introduced with the movie, he couldn’t very well be killed off before his toy model was available. That would just be crazy! Unfortunately most of the other Transformers killed in action didn’t have this exceptional circumstance, and thus were dead for good. Except for Optimus, of course.