The Reng Dei is a river in northern Cylemia, that is a tributury of the Reng Fync. The river flows through the Northwood, meandering gently pass pines, oaks and spruce trees. The Reng Dei flowes in a south-westerly direction, flowing for nigh on a hundred miles, where it runs into the Reng Fync. The Reng Dei begins in the Five Needles, a series of hills. The city of Erec Dei is built on the western bank of the river, near a ford. The area has become the scene of recent fighting, as part of the Twin Queens' War. The area primarily supports the older Queen, Thyselia.
The river is named after the Queen Dei, a warrior queen three thousand years earlier. Legend has it that the elf queen secretly loved a dwarf bard called Loc, from the city of Banardhal. A war broke out between Cylemia and Banardhal, and the Queen met the dwarf army near modern day site of Erec Dei. The battle, called the Battle of the Red Fords, took place there. In the midst of the battle, the queen killed a dwarf clad in armour, who was reveiled to be Loc. The queen was said too have cried so hard her tears flowed into the Reng Fync. This is how the river supposebly came into being.
The Reng Dei begins in the iron and copper-rich hills of the Five Needles. It begins in Queen's Tears, a waterfall that flows from an unamed subterrean lake. It cause a small valley, and then flows through the Northwood. It meanders softly in a south-westerly direction. Its banks are lined with small farms and hamlets, that use irrigation from the river to grow crops. A small lake, called Lac Murnius, has formed around twenty miles downriver from the hills. The township of Murnius has been built as a bridging point across the river. The city of Erec Dei is built on a natural small plain on the west side of the river, surrounded by two stone walls. The river enters the Reng Fync after ninety-six miles.