Answer
In the Transformers franchise, Frank Welker voiced Megatron, Galvatron, and Soundwave. Megatron is the leader of the Decepticons, and Galvatron is his successor. Soundwave is a Decepticon spy and communications officer. Welker has also voiced other characters in the Transformers franchise, including Optimus Prime, Bumblebee, and Ratchet.