Sieges take place at the castles of Gludio Castle, Dion Castle, Giran Castle, Oren Castle, Innadril Castle, Goddard Castle, Schuttgart Castle, Rune Castle, and Aden Castle. There are also unique clan halls where ownership is acquired by battle with NPCs.

Only clans of level 4 and above can officially participate in a siege. Clans that are less than level 4 or players not belonging to a clan may still participate as non-related parties, but they do not have the right to own a castle.

Unless the castle is captured by a clan, it remains in NPC control.

If there is a PC clan that defeats the NPC clan and occupies the castle according to the rules of the siege, the castle becomes the property of that PC clan.

The very first castle lord must, within 24 hours of becoming castle lord, designate the time for the next siege. If this is not done, the default siege time will be applied automatically.

If a clan that occupies a castle is dissolved, the castle returns to its initial status.

The challenging clan leader must have earned the level 4 clan skill Seal of Ruler in order to take control of a castle. The clan leader must visit the siege registration NPC (titled "Messenger") near the castle to sign up for the siege. Siege registration must be done 24 hours before the siege begins.

Any clans that wish to aid in defending the castle must register their clan as defenders.

Each clan wishing to participate must be a level 4 clan. To participate as a defender in a siege, talk to the registration NPC outside the castle gates. (The castle lord must approve participation.) Defenders must register 24 hours prior to the beginning of the siege. The castle lord must approve and finalize the siege defender list 24 hours before the siege begins.

The clan occupying the castle does not have to register -- it is automatically listed on the siege list and cannot be taken off of the list.