Army faction cape

As far as I can tell, it doesn't really matter which one you pick, aside from
the fact you can't attack anyone who has the same color cape on. The exception
to this rule is the Prodigy cape, which allows you to attack or be attacked by
anyone, even other prodigy cape users.

While wearing a cape, you can be attacked by anyone else who has a cape of a
different army on.
Removing a cape from your equipment slot takes about ten seconds, and can not
be done less than twenty seconds after exiting combat. This is to prevent
people from donning the cape, pegging someone with arrows, then removing it
quickly once they find out their target isn't dead.
Donning the cape, however, can happen instantly. This leads to a lot of people
not wearing their cape until they see someone else wearing a cape they desire
to attack, then sneaking up behind them, putting the cape on, and getting in a
couple blows as a head start. My pride is far too valuable to let people like
this get away, making the need for windwalk and universal pills in the inventory
a must to remove the cold, frozen, paralyzed, or stunned effect the offender
leaves on you a must.

These capes are only FIVE HUNDRED GOLD at the grocery store NPC. Do not spend
any more than this at the numerous stalls that have them in stock for 1,300 or
more.
You must be level 10 to use an army faction cape.

If you are killed by another player, you may resurrect immediately where you
were killed. You will not lose experience as a result of dying to a player
killing you.
http://www.gamefaqs.com/computer/doswin/file/930711/43300