Soundwave (Change of Heart (TT story number 3) and beyond)

Soundwave is one of Megatron's most reliable troops, and he has positioned himself comfortably and irreplaceably in the Decepticon upper command structure. He's also the communications officer for Hydra Island, and the commander for a small group of Decepticons often referred to as the Casseticons (Laserbeak, Rumble, Ravage, Buzzsaw, Frenzy, and Ratbat), most of whom are used as spies. His alternative mode is yet to be determined, though it's most likely going to be a Microcassette cassette deck.

Though stoic and possessed of little outward personality (as evidenced by his monotone computer-style speech), Soundwave is not without drives: he has worked hard to get where he is, and he guards his place in the Decepticon hierarchy fiercely.

His voice should at least come close to sounding like Frank Welker with a robotic vocoder tone/pitch.