Cain

He first bumps into Julie in the hospital car park but she speeds away as she asks for change. 
 
Later he visits the home of a conspiracy theorist who is looking into the Moon Lake incident and with his metal covered hand takes his head and energy flows out until it explodes. When investigators arrive at the scene they find a skeleton and strands of matter, almost crystalline, radiating out in all directions. 
 
He then follows Julie on foot to the motel where she and Dillon initially hide out and massacres the bikers before facing off with Julie. Their powers fire at each other and Julie's seems the stronger as it blows him through a wall as she protects Dillon and then blows the whole building away. 
 
The next day when Ivy appears on the scene he rises from deep under the dirt but maybe a mile or more away. 
 
He almost catches up with them again but as soon as Julie notices him and gets in the truck the suit decides to take him down with a massive blast. An unfortunate driver stops at the crater sometime later and is killed by Cain who takes his car and catchup up with them again. This time he knocks Julie down into the ground and tries to take hold of her, causing an explosion after which Julie recovers and Dillon notes she now seems to have more metal on her body, possibly from Cain. 
 
He later target Vijay as one of Annie's coworkers and kidnaps him intending to sacrifice him as an affront to god. He rants and talks of his brother Able and the curse and his long history. He waits until Julie and Ivy come close to his location to start cutting Vijay. Julie blasts him in the back and into a fire. His chard corpse remains alive until she takes his hand and takes the last of his metal and Ivy shoots his corpse into dust. 
 
His finger remains and Ivy has it tested and tis found to be 27,500 years old. 
 
Julie and Ivy discuss if he could be the original biblical Cain but Ivy points out inconsistencies between biblical accounts and the white man they faced. 
 
She alter researches Cain and find out a prophecy that if he is killed by a child decedent it marks the start of a 7 day count down to the end of the world, which coincides with the date of the phi colliders switch on.