The Emperor Worm is the leader of the Worms.
Unlike the other Worms, the Emperor is "large and in-charge". He is hugely fat, and almost double the height of the worms. He usually shows up un-announced to the MiB. Here he usually brings two big cases which the agents always carry in. The Emperor is careless and defenseless, so the other Worms must watch him. He is also disappointed in the Worms, as Coffee is only reserved for royalty.
When he first appears in the Big Bad Bug Syndrome, he seems incapable of human speech, but when he re-appears in the Mine, Mine, Mine, Syndrome, he becomes capable of using English vocabulary, albiet mostly incorrectly, saying "good aftershave" instead of "Good afternoon."