Shadows of War Part 1
The structures that have popped up on the main world signaled the start of the war with the undead. At first the undead players were confused because they did not think that there would be two factions of undead. They thought that the Undead War was about the war between the living and the undead but it was actually a literal war of the undead.
Another interesting fact was that Undead players could not easily join guilds allied with kingdoms since they are exterminate on sight kill order. Those who also changed their race to undead have been automatically kicked out from their guild as Undead are considered the enemy of the living.
This is also one of the reasons that Adrian is being careful of being recruited by a guild because his race would be automatically seen once he joins one. He would be able to get accepted but once he is accepted then he would be immediately kicked out because of his race.