Pirahnacon was with Unknown's Decepticons (if you remember TNB), though was probably the most forgotten Decepticon in that era. (also Dirge, because I made Dirge be in that series and he also is forgotten.) He's a decepticon that remembers their past, which is a uncommon thing. (Only Jazzimus remembers his past, and he's the real main character.) Pirahnacon and Lunge attacked Alonia and defeated her, somehow. He, Eaglekiller, and Alericus would try to kill Jazz again, but would fail. He and Xenomorph would attack Flashbee, Skyler, and Carsurge. Flashbee would set up some bombs, but the Sea-bot would see and defuse them. He and Prey would attack the Medidrones and Autoguards. Kzonia and he would attack Brightlight, the other Alonia, and Sehria. Jazzimus would attack Pirahnacon and a few Helicons.
He'd a Decepticon, but he's not really Evil.
Grey and Purple.