Generally speaking, Herobrine is widely believed to be the ghost of Notch's brother, Notch being the creator of Minecraft. However, the Haunting/ Haunted continunity seems to reflect something else. According to the series, Herobrine was originally a demon originating from the Demon Realm, who was in some way summoned by Collin, who then possessed Collin and killed his family, except for Armen. However, sometime down the line, he took on the name Herobrine and led a ruthless army that destroyed several cities, even burning their citizens alive. However, he was thwarted by the unknown weilder of the Cross of Mercy. Why Herobrine remains even after his apperent death is unknown, and his motives for doing all the damage he's done also remain unknown.
Herobrine was first seen outside Drake's window, fighting and killing some skeletons. He continuously haunted Drake and Armen at night while they remained within their house. He eventually trapped them in some underground passages before forcing them to fall into the void.
The Haunting 2: Second Life:Edit
Herobrine continues to haunt Drake and Armen, and successfully trapped them in the Nether for a short period of time, during which they "killed" him, however he returned to life to kill one of them and torture the other for eternity. This did not seem to have happened, as both Drake and Armen woke up from Herobrine's palace in the town of Ruby Shire.
The Haunting 3: Legend of Herobrine:Edit
Herobrine has been spotted most in these episodes and in the end when Armen sacrificed himself for Drake and Grayson and at that point Herobrine had merged with Armen
As seen in episode Herobrine, acting though Armen, caused widespread descruction thoughout the Badlands. However, 2 years after the events of the Haunting 3, Drake confronted Herobrine though Armen but wasn't able to defeat him. It's likely this happened because Drake no longer had any weapon capable of defeating Herobrine. It's unclear if Herobrine will continue to stalk Drake and Grayson, but it seems to be a secondary objective to causing widespread ruin. He also seems to be very powerful because (part of Him being split away, most in Armen, the rest in Drake), he can seemingly control both Armen and Drake, even with very little as seen in episode 5 "memories" in the very end. He may have also been the tormentor to Drake and Armen in Origins and to Drake and Grayson in Temptation, attacking in Origins and taunting in Temptation.
The Haunted: Shadow of Herobrine: Edit
Herobrine is revealed to have currently escaped Armen's body and went into hiding.
Taking Vessels Edit
It is possible that Herobrine can not exist in the mortal world as he can only exist in vessels. In the Haunting 3, Herobrine's vessel is destroyed by Armen, but Herobrine then enters Armen in order to survive. This would imply that Herobrine can only exist if he has a vessel, making it possible that original Herobrine took Collin's body in order for him to be animate.