Morgoth 's Orcs took the mountain forts on Mount Rerir .
Morgoth 's Orcs defiled Lake Helevorn , then advanced south through Thargelion and into East Beleriand over the fords of the river Gelion .
Morgoth 's Orcs took the mountain forts on Mount Rerir , and defiled Lake Helevorn , then advanced south through Thargelion and into East Beleriand over the fords of the river Gelion .