Bān is pretty much the same as mēda, except it refers to people who are not us, and to a lesser extent people who are not “me”. Generally if the “not me” person is still a part of the “us”, bān isn’t used. Bān is generally and specifically people (or entities) that are recognisable as like “us” but not enough to be included as “us”. For example, the name of the Bear Ancestor Totem is Abān, which literally means that Bear is like us but not one of us, because bears are sometimes bipedal, and if you watch a bear’s behaviour (while not being a threat, of course), you can easily see their humanity, their feelings. But they’re furry, and tall, and strong, and just as likely to rip your head off as to sniff you for a while and wander off. So the Bear Totem is made different from the others because they’re called a name that says they’re the most “like us” out of all of them.
Bān also pertains to drawing the line between us and them. For example, on Planet Shadow, there’s a terrorist group called the Rona-Abaan, and this literally translates as “those Ronan who are separate”.