The FINAL FANTASY XI development team created the "Assault" system to provide a means of casual enjoyment for high-level players--the main target audience of the Treasures of Aht Urhgan expansion disc. Assault allows for parties of three to six members to enjoy gameplay that does not last a long period of time and requires little recruitment effort. Players can choose the location, decide whether or not to impose a level restriction, and select the type of Assault mission to fit with their objectives and party organization.