I setup the groups here:
http://pastebin.com/C3RzueSq

I gave each rank its own permission node, but when players with different ranks login it always shows the player prefix, but it works for mods

Hello,

Based on this file. Your default players would be shown as Mods.

It needs to be from highest rank to lowest rank.

Don't I need to give the permission nodes to each group?
It's player -> knight -> baron -> mod
So I gave the nodes to each of those groups but players who are baron/knight still show up as a player.

Edit: I see what you meant by order, looks like its all good now thanks :)