Jagex has announced that RuneScape's Clan Citadels expansion is scheduled to launch on July 26, and this update promises to add all sorts of new content to the free-to-play game. For example, it will introduce floating customizable clan castles that come complete with portal grounds, meeting rooms, senates and party rooms. It will also feature clan battlefields:

"The centerpiece of the expansion is the clan battlefields, a unique sandbox environment allowing clans to generate their own user-generated gameplay for the first time within RuneScape. Clans will have access to a full-blown Battleground Editor equipping them with all the tools needed to create and develop their own multiplayer games. Clans can create any gameplay they wish; ranging from simple capture the flag style games to full clan versus clan battles. Once created, clan members can save their games and even invite others to compete in their creation."

For more details on Clan Citadels, read the in-depth dev blog entry and watch the trailer below.