The dragon is Satan. The color red is associated with death for it is the color of blood. The seven heads represent seven kings and their kingdoms all subordinate to the dragon. The 10 horns likely reflect the 10-nation empire led by Antichrist, Satan’s appointed leader on Earth during the coming Tribulation.
One day the Rapture will happen and many people around the world (i.e. Christians) will disappear. Most people left behind will choose to follow Satan and his antichrist. Devil means accuser and Satan means adversary so clearly this character is no one’s friend. Oh, the horror that awaits those who align with them. They will regret it forever.