They are found in the Legends Guild basement, and are quite weak. They have a high amount of hitpoints, but quite low defence.
They drop large amounts of airs, as well as some cosmics. Bloods and deaths are sometimes dropped too. Gold charms are common, as well as some crimsons. Occasionally herbs are dropped, ranging from Guam to Ranarr. Sometimes they drop a mithril bar.
For some reason, they do not show up on the minimap, and they can be hard to see. Luckily, there is no competition for them.