"Also known as The Virus (Before the true origins of Herobrine and Endermen are known), Master (By Possesed), Him (In Ryan's log), Ryan 2.0 (By Ryan)
First a clone of Brian, the main protagonist. Herobrine was created by Ryan in secret, in an attempt to create a being more powerful than anything, he soon went out of control took control of Mark's body, killing Ryan.
Herobrine serves as the main antagonist until the final chapter, where he both serves as an ally, and the secondary antagonist.
ROLE IN CHAPTER ONE: We first see Herobrine in the opening scene, trapped in a cage asleep. Then we see Mark and Ryan having a discussion, then Ryan tells Mark to go down in the power central to activate the machine. Sadly, Herobrine wakes up and possess the closest entity, in this case Mark. Ryan goes down to check, but is then murdered by Herobrine (Now in Mark's body). Almost the entire episode goes before we see Herobrine again, in Brian's Vision from the enderman. You can just see him standing there in the end, before the episode stops.