Xa-Tul is a major antagonist in the Gameknight999 series. He appears as the secondary antagonist of both Trouble in Zombie-Town and Last Stand on the Ocean Shore, a major antagonist in the Herobrine Reborn series, and the main antagonist of System Overload. He is a zombie-king created by Herobrine.
The Mystery of Herobrine
Trouble in Zombie-Town
In the first book, Herobrine is dissatisfied that Erebus and Malacoda failed him in the previous books. So Herobrine creates Xa-Tul by killing several zombies and crafting a new zombie out of their XP. Xa-Tul then gathers all the zombies he can to the one zombie-town so they can help Herobrine find and capture the User-That-Is-Not-A-User.
Later, Gameknight's sister Monet113 is sucked into the game and ends up disguised as a zombie, thanks to a mod Gameknight had created. Monet is mistaken for a zombie by the other zombies and brought to the zombie-town.
When Xa-Tul gives a speech to the assembled crowd of zombies, Monet speaks out against him to try to defy his authority. Xa-Tul threatens to kill Monet, but she is rescued by Gameknight, Crafter, Hunter, and the Woodcutter twins.
Xa-Tul and his zombies pursue Gameknight, Monet, and their friends to Crafter's village. Gameknight fights Xa-Tul and almost kills him, but Herobrine rescues Xa-Tul and teleports with him to safety.
Last Stand on the Ocean Shore
Despite being absent in the second book, The Jungle Temple Oracle, Xa-Tul reappears in the third book, Last Stand on the Ocean Shore. Herobrine sends Xa-Tul and his zombies to capture Gameknight999 and Monet113, hoping to use them to escape from Minecraft. Xa-Tul catches up to Gameknight at a desert village, but Gameknight escapes. Later, Xa-Tul lies to Herobrine about what happened to prevent himself from getting punished.
Herobrine later makes Xa-Tul one of his Four Horsemen of the Apocalypse, along with Feyd, Reaper, and Charybdis. They rally their monster armies to the beach village where Gameknight and company are currently residing. During the ensuing battle, the monster army is overpowered by the users, NPCs, and iron golems, and Herobrine is trapped in the body of a pig.
Gameknight gives a speech to Xa-Tul, Feyd, Charybdis, and Reaper about how his friends and family will always protect him, causing their armies to retreat. Xa-Tul vows revenge on Gameknight before he and the other Four Hoursemen leave.
Xa-Tul shows up again in the first book. When Gameknight999 and his father, Monkeypants271, enter the game, Xa-Tul and his zombies lead an attack on Crafter's village. Gameknight and Monkeypants escape with Crafter, Hunter, Digger, Stitcher, and Herder.
While Gameknight and his allies are in the witch Morgana's swamp territory, they are safe from the monsters; however, Xa-Tul joins forces with Feyd to track down Gameknight.
Xa-Tul and Feyd track Gameknight and his allies to the End, but they are too late; Gameknight had already pushed Herobrine into the Void.
Destruction of the Overworld
In the second book, Herobrine has sent his XP out and possessed the Enderdragon. Herobrine returns to the Overworld and forces Xa-Tul, Feyd, and Reaper to join him and his monster army in destroying every village they can. In the end, however, the monsters are beaten and Herobrine's XP is trapped in an Ender Chest.
Gameknight999 vs. Herobrine
In the third book, Feyd brings Xa-Tul and Reaper together with the new spider-queen, Shaivalak. They monster-kings plan to steal the Ender Chest with Herobrine's XP from Gameknight and his friends. They ambush Gameknight's entourage at Two-Sword Pass (or Vo-Lok's pass, as the zombies call it). However, Herobrine possesses Herder and forces him to take the Ender Chest to the Nether.
In the Nether, Xa-Tul's, Feyd's, Reaper's, and Shaivalak's army joins the Nether monsters in trying to vanquish Gameknight once and for all. The monster army is defeated when Monet113 brings in a horde of users to defeat the monsters. Xa-Tul, Feyd, Reaper, and Shaivalak escape.
Xa-Tul returns once again in the third book. He acts on the orders of Herobrine to bring all the zombies on every server to the one server. Xa-Tul kidnaps NPCs to dig tunnels to fit all the zombies. Herder is one such NPC. While digging, Herder learns that Xa-Tul's plan is to overload the server and make it crash, causing the whole Minecraft software to reboot and every mob to lose their consciousness.
After Gameknight finds out Xa-Tul's plan, he leads an army of NPCs to kill the vast number of zombies. In the zombie-towns, he is joined by Feyd, who discovered Xa-Tul's plan and realized that the Minecraft software crashing would kill everything-including the monsters. Xa-Tul almost kills Gameknight, but Feyd saves his life and pushes both himself and Xa-Tul into a portal that leads to another server. Acting on Feyd's words, Gameknight breaks one of the blocks that makes up the portal that Xa-Tul and Feyd are going through. This kills buth Feyd and Xa-Tul.
- In the foreword of Mission to the Moon, Mark Cheverton states that Xa-Tul was his favorite villain to write.
Minecraft: Story Mode