You were subject 111 along with with many others, but the difference? him and you had a romantic affair but when Brenner discovered your secret meeting with Creel he realized he might lose you to Creel and told you Creel was a distraction to your power as you were becoming too powerful to gain powers more like telekinesis and closer to harnessing powers like teleportation and reality warping. Because of your greed to powers you decide to tell Creel one night that you can't be with him anymore. But that night he ends up opening a door to another dimension in Hawkins Lab and abducts you as he had overheard Brenner manipulating you. Despite being a psychopath he truly loved you and the fact of your greed breaking their bond enraged him to death. After the abduction, he ties you using the dimension roots against a tree and you open eyes as you had previously fainted and look around not identifying the place when he growls from back

"Surprised love?"

Your eye widens as you see his real form while he smirks walking round you like a predator around it's prey