At the moment, alts are available only with certain limitations. Specifically, alts are available only to current players of Dornish hostages or to players of other characters who wish to play a Dornish hostage. Players are allowed one character with a tier higher than IV, though since all hostages are Restricted, players can have more than one character who is not Open. See the Alt infofile for more information about the general alt requirements and restrictions.