3. Parasite
Parasite could be in the future for many reasons. The main one being - he's a man from Metropolis. Rudy Jones was a maintenance worker over at S.T.A.R. Labs who chose the path of evil before ever becoming Parasite. After stealing materials out of the labs to sell on the black market, Jones is doused with the chemicals in which he stole and becomes Parasite. His ability is harnessing the essence, power, knowledge, ability and life of anyone he touches, killing them in the process. Without doing so, he himself would die. He continuously searches for the ultimate power source, Superman.
How would you introduce him in the movie? In a desperate attempt to save his own life, Parasite is discovered draining the life form from anybody he can get his hands on in Metropolis. He eventually realizes that Superman is his salvation. The ultimate battery that he needs in order to survive. Drawing Superman out, he grabs a hold of the Man of Steel, temporarily draining Superman of his powers. After his first taste, Parasite is obsessed with wanting more. That's when the fun would start.