As requested by Irish-Changeling, here is all the information I’ve been able to glean about the Chasind from the various books I have. Sadly, “World of Thedas” has only a single paragraph (that I’ve been able to find, anyway). However, the Green Ronin RPG books were a richer source of info.
From “World of Thedas” - Chasind (In the “Humans” section):
Some members of the Alamarri tribe, called Chasind, resisted the unification of Ferelden, retreating to the Korcari Wilds in the south. There they continue to live a peaceful, if misunderstood life in small communities. Their leaders are shamans, respected in Chasind culture for their magical abilities.
From the Green Ronin DA RPG “Game Master’s Guide V. 1” - Chasind Stalker (in the “Adversary” section):
The Korcari Wilds do not suffer fools lightly and the Chasind peoples who make their home there are a hard folk, ill disposed towards outsiders. The harsh conditions of the Wilds and the primitive nature of the Wilders incline them to take by force or stealth anything they cannot grow or build for themselves - which is to say, almost everything worth having. Chasind raiders, known within Ferelden as “stalkers,” often slip out of the Wilds traveling in small scavenging parties to search for easy targets amidst the freeholds of the south. The Wilders are famed (and cursed about) for their stealth and hunting skills, both of which they employ to track down suitable targets. They favor vicious ambushes using short bows with wickedly hooked arrows. Stalker groups are invariably small, to deflect attention, and likely to be lighly armored in patchwork leather, so as to move with speed.
From the Green Ronin RPG, “Player’s Guide 2” - Chasind Wilder (in the “Character Options” section):
The Chasind are a barbarian folk that live to the south of Ferelden in th Korcari Wilds. While they did unite on several occasional with the Avvars and the Alamarri to fight against the Tevinter Imperium, Fereldans have stronger memories of the many times the Chasind surged north into their land. It is said that ages ago the Chasind conquered the Alamarri, the ancestors of the modern-day Fereldans, until the latter rose up in rebellion. Later the legendary witch Flemeth led an army of Chasind into Ferelden to take vengeance on the bann who had been her husband. While Flemeth is said to have been killed at that time, many claim that she and her daughters (the Witches of the Wild) still live amongst the Chasind. Today the Chasind are a more peaceful folk but there are many superstitions regarding them. They live in houses build on stilts and do some trading with Fereldans living in the south. Some Fereldans still consider the Chasind a threat and fear the day a charismatic figure will unite them once again.