Dragonlands
This group has intruded into the Nan Lefnui bringing an army, a menagerie and a cruel culture. It overwhelmed the fortress at the mouth of the River Lefnui in a surprise attack and has noved, slowly upriver ever since. Their initial invasion seemed aimed at establishing a landing place for a party intent on hatching some Dragon eggs in the region. When this plan was thwarted, they retreated to their ships and captured towns and then, with reinforcements from wherever they used to live, Orcs and Trolls gathered to their standard - and treacherous Dunlendings, they have started moving north up the River Lefnui capturing the various Gondorian settlements on route.
Culture
So far, little information is available about the culture - there is no intercourse between the Dragonlands and the Kingdom of Gondor besides war. All Humans are either Slaves or Vassals or Dead. Rumours that they are led by a wraith, or a twisted Elf or a depraved Human are all unsupported by the evidence to date.
Assets
The Dragonlands appear to have access to domesticated Dragons. It is this feature of their organisation that has resulted in their name.