Megatron died in the first movie. The second part has come back to life. But he didn't die. He ran away.
It shouldn't be much at first. All those old faces. Because Sentinel Prime used that thing to bring Cybertron's Decepticons to Earth.
Those who drink Shuhua milk are lunar researchers or something. It was he and another group of people who brought the Decepticons to the moon and the energy column to the earth. Finally, the Decepticons killed all the people related to the earth in order to destroy the evidence. That disgusting sissy is one of them. .