We already got to know the main antagonist of the Shadowlands add-on when the add-on was first officially announced at BlizzCon 2019. The Jailer was introduced to us quite enigmatically. At the announcement we could also see his silhouette, but now he looks a little different.

The previous week saw the release of Shadowlands and with that we were able to learn a little more about the character. 

The overseer's name is Zovaal and he belongs to the pantheon of Eternal Ones (org. Eternal Ones). The Eternals are somehow connected to the First Ones, who probably created the Shadowlands and the entire Warcraft universe. 

In addition to the Jailer, the members of this pantheon include:

  •  ARBITER - He was the one who judged the souls who ended up in the Shadowlands after death. His indisposition caused the anime crisis and the corruption of the "death machine". 
  •  KYRESTIA - He leads the Kyrians in the land of Bastion. 
  •  KINGDOM OF COLD - Takes care of the All-New and leads the Night Fairies. She calls Yser "her sister's pet", which may mean that her sister is Elune. 
  •  DENATHRIUS - He is the creator and leader of the kingdom of Revendreth. 
  •  PRIMUS - The lost founder and ruler of Maldraxxus. 
  • Zovaal was once a disciple of the Arbiter.
  • Both the Supervisor and the Arbiter have a similar hole in their chest. Except that the Arbiter's hole has a pearl inside, while Zovaal's is empty.
  • His fellow humans were forced to lock him away in the Hells for treason.
  • We do not yet know what exactly the Supervisor did to anger the rest of the Pantheon. I think we've already seen the effects of his actions in Warcraft, and it was something that affected the entire universe in some way.
  • Primus believes that Zovaal was not acting alone at the time and that he had allies.
  • Zovaal became a prisoner of the Vale, but also its overseer, and locked the souls of the meanest beings in the tower of Torghast.
  • He kidnapped Runecarver and commanded him to presumably create the Helmet of Domination and the Frost Blade. Devos, in the movie Beyond, called them "the weapons of the Vale". Furthermore, the runes on the Blade match the runes on his body.

The Shadowlands Collector's Edition of the Art Book includes this quote:

"The veil between realms wanes. The Helm of Domination was created to be our way forward. Instead, the one seared by the flames of life uses it to keep us at bay."

We don't know who is saying these words. Perhaps the Jailer himself, or perhaps one of his servants.

Jailer has characters like Sire Denathrius, Helya, Mueh'zala, Kel'Thuzad and of course Sylvana on his side.

Sylwana has been working with him since she jumped from the Crown of Frost in the Wrath Of The Lich King supplement.

It was he who directly or indirectly set Sylwane up as the new War Chief of the Horde by manipulating the dying Vol'jin.

All of the decisions Sylwane made were with the goal of delivering as many souls to the Horde as possible.

Zovaal turned his chains into a weapon with which he defeated Primus.

He probably would not have succeeded without the power from the "broken death machine". 

The Shadowlands add-on has only just launched, so we'll learn more of the story as we get more updates, raids, etc. If you think a detail should be added, leave a comment under the Facebook post.