Clan Citadels were first introduced in a teaser on the RuneScape homepage. In the news post announcing the impending update, The RuneScape Team stated that the update is be members only and claimed that Clan Citadels would be very customizable and would be tiered. It also showed that clan members would have to collect resources to build them.
There will be dozens of hotspots for you and your clan to make your own. Of these hotspots, a maximum of seven are skill-related, allowing players and their clans to train skills together. Although the experience received is be slightly lower than would be received on the surface of RuneScape, skilling there contributes to the maintenance of the citadel, allowing players and clans to upgrade it from tier 1 to tier 7. As the citadel gets upgraded, players and clans gain access to better customization options and even more hotspots. Contribute enough to the weekly upkeep of the citadel and players will have access to a clan ring, which gives a temporary 1.5x multiplier in certain skill tasks about RuneScape.
There will be over 4,000 new models and over 20,000 new animation frames added to the game for Clan Citadels.
Clan Citadels may be the first content in RuneScape to feature sky boxes, as the Clan Citadels teasers contains them, and Mod Nexus stated "The video footage is all from in-game. We didn't "cheat" or use post effects to make it look prettier or shinier, it really does look like that."
It has been confirmed by Mod Timbo that Clan Citadels cannot be officially named in-game. He also stated that the Clan Citadels would be given some lore references before its release the "tons" of them after they are released.