Sinn are a form of flying necromantic being, taking the shape of a skull with tentacles. They use weak magics on the whole, but can be dangerous in numbers or as backup for more dangerous foes.
Gor Gammar's surrounding lands are a favourite haunt of these creations, near roads.
Take care in approaching, as their lightning spells can cause weak but fast damage. By the time a player can survive down in the south, they should pose little threat.