Joint Investigation Group
The Empire-Empyrean Joint Investigation Group is an alliance between the De Los Empire of Arad and the ruling government of Empyrean formed for the express purpose of exploring the Castle of the Dead. To this end, they build a base on Zelva, the remains of Anton that are so large they have formed an entire island near the Castle of the Dead.
The Joint Investigation Group also collaborates with the Adventurer's Guild and Grim Seekers towards the common goal of investigating the Castle of the Dead. However, after learning about the threat of the resident Apostle, Luke, it quickly becomes clear that the groups have different goals. The Joint Investigation Group's position is that Luke and all Apostles are invariably threats to Arad and Empyrean, therefore Luke must be killed.
The player can choose to join the Joint Investigation Group during the Castle of the Dead arc. Between the Joint Investigation Group, Adventurer's Guild, and Grim Seekers, the player is required to join one and only one faction. If the player auto-completes this part of the questline or was created as part of the Fantastic Jumping Server event, the game will automatically assign the player to the Joint Investigation Group.
- Imperial Princess Isabella — The 3rd princess of the De Los Empire and the primary representative of the Empire in the Joint Investigation Group.
- Cyrus — The childhood friend and personal bodyguard of Isabella.
- Vaughn Walshuted — One of the Four Legendary Blade Masters who defeated Fifth Apostle Sirocco, he leads the Iron Wolves who were sent to Zelva to protect Isabella and help investigate.
- Hartz von Krueger — The Vice-Captain of the Iron Wolves, working directly under Vaughn.
- Nevillo Jurgen - The current Regent of Empyrean, a member of the nobility and the primary representative of Empyrean in the Joint Investigation Group.
- Hiram Klauf - One of the captains of the Empyrean Coast Guard who comes to Zelva to assist in the fight against Luke.