Complex sentence: The Decepticons are a faction of evil Cybertronians who mostly turn into military vehicles, construction vehicles, expensive luxury or sports cars, and even smaller-than-human-sized objects.
Split into simpler sentences: The Decepticons are a faction of evil Cybertronians who mostly turn into vehicles. They often turn into military vehicles, construction vehicles, expensive luxury or sports cars, and even smaller-than-human-sized objects.