Animated Mithril Armour is found at the Warriors' Guild. In order to summon it, you must put a mithril full helmet, mithril platebody and mithril platelegs on the Magical Animator. Although this is a fair way to gain Warriors' Guild tokens, there is a chance that any piece of the armour may break during combat. Note that you will get your armour back most of the time after fighting. This is a very good way to gain warrior tokens since the animated mithril armour is relatively easy to kill but still awards 50 tokens.