Permissions are handled through a multi-layered permissions tree.
Oathbreaker has no inheritance, and no other group inherits from Oathbreaker. The first, and default, group is
Adventurer.
As you can see in the picture, Adventurer is the default group.
Guide inherits permissions from Adventurer.
Artist inherits from Guide. Then there is a split between the creative and authoritative roles. Enforcer gets permissions from Artist, and the
Head Enforcer gets permissions from Enforcer. Likewise for the creative roles,
Designer gets permissions from Artist, and the Head Designer gets permissions from the Designer. There is one 'super role' which is Root, who has all the permissions inherited from everyone.
The permission system is a YAML formatted text file, which records every non-default ranked player. Default ranked players are not saved (determined by deduction).
The permission system also uses negation permissions, which is basically an entry that eliminates a previously acquired permissions. This is extensively used for the Oathbreaker group, and is also used throughout the permission hierarchy for other ranks.