Rollbacks have the ability to undo useless edits with one click of a button. They are also second in command, after the admins. Rollbacks don't always have to be active, 100% of the time, so it's a good position for spontaneous editors who like to contribute randomly to the wiki.
Rollbackers (users with Rollback rights) can be seen via Special:ListUsers, but they do not by default have any special title that appears on their userpage. http://disney.wikia.com/wiki/Help:User_access_levels#Rollbacks
Rollbacks are users to contact when Admins aren't around and you spot vandalism. They patrol Special:WikiActivity a lot to be able to spot vandalism easily.
All Administrators automatically have Rollback permissions. They will not be listed here. Also, most Chat Moderators have Rollback rights. They will not be listed here either. To see a list of Chat Moderators please visit here. To view the list of Rollbacks visit http://disney.wikia.com/wiki/Special:ListUsers?group=rollback.