Arbiter
Overview
Arbiters are the highest ranking troops in Arachnos. They are supposedly linked directly to Lord Recluse, and to even try to harm one would be the same as challenging Lord Recluse himself.
Arbiters are in charge of keeping things orderly for Lord Recluse, and oversee most everything that goes on within Arachnos. They are said to be above factionalism. That is, they never attack "Destined Ones" (player villains), or each other.
The basic Arbiter uniform is a white-on-white version of the faction they are from with a (generally) turquoise cape that has the Arachnos emblem, and the two types are Fortunata and Wolf Spider-looking Arbiters. Fortunatas are called Fortunata Fateweavers, and change a given player's mission difficulty for a small fee. Wolf Spiders are referred to by their name (ie: Arbiter Diaz).
Gameplay
Arbiters function as either mission difficulty people, as above, or the Trainers of City of Villains for players. Some zones have more than one.