Bilrach

Bilrach is a Mahjarrat mentioned in Zemouregal's Notes - Part I. His entry describes him as follows:

Bilrach has yet to be observed in-game, but may be involved further in Zemouregal's plans for The Ritual in The North. He follows Zamorak, because Zemouregal is also a Zamorakian Mahjarrat.

Some players suspect that Nomad from Soul Wars is Bilrach in disguise. A clue from one of the Chaos Elemental's Postbags can be deciphered to read, "You've been warned about Soul Wars. Nomad is to be feared." Although there has been no evidence ever provided for this, there are some hints such as the fact that during the final fight of Nomad's Requiem Nomad uses an Ice Barrage-like attack on the player. The ancient magicks originated from the Mahjarrat, suggesting that he may be a Mahjarrat. This is confirmed by the notes found during Dungeoneering.

Since Bilrach is Zamorakian, he could be considered the player's enemy (and thus feared) because the player seems to be an ally of the Zarosian Mahjarrat.

Other clues have led players to believe that Romily Weaklax of the Cooking Guild could be Bilrach spying on the defenses of Varrock, but this is also purely speculation.

Role in Dungeoneering
In the dungeoneering skill, the player can recieve books called Chronicles of Bilrach. It appears that he is responsible for constructing the tunnels at Daemonheim. As of yet, because the update is still new, it's unknown whether the player is capable of meeting Bilrach. He ends his messages with the phrase "Zamorak be praised," so it appears he is still loyal to Zamorak. During his entries he also calls Zemouregal a fool who understimates his skill, meaning maybe Bilrach is only going along with Zemouregal to gain power and might betray him, seeking his own goals. He also claims the purpose of building the tunnels are to reach a powerful treasure deep below the castle of Daemonheim. Some speculate that during the time he was writing these notes he was pursuing the Stone of Jas.

If Bilrach is responsible for summoning the various demons in Demonheim, the large number of Forgotten warriors, mages, and rangers, and has also converted the Kael'Geron demons to his will, it can be assumed that he has reached a state of power that is as great as Lucien or Zemouregal, and maybe even Azzanadra. Though, seeing as information is still limited at this time, this cannot be ascertained.

In Lexicus Runewright's journal, received in the Dungeoneering Skill, Lexicus mentions a man named Bill who is the master of Daemonheim, it is highly likely that this is Bilrach. In addition, Lexicus gives the player clues as to what Daemonheim is for and more on Bilrach's nature. He mentiones that Bill 'believes it will be the magical discovery of a thousand lifetimes'. On page six of the journal he then says 'Astea and I must confront him' after saying that 'Bill would cast us all over into the darkest of darkness.

This seems to fit with what was said by The Chaos Elemental, further supporting the theory that Nomad is Bilrach in diguise.