The Nasgareth may look like elves, but instead were created by an entirely different divine being, which admired the elvish looks and traits, but wanted to create his own army instead. One without Love.
As they travel they notice a horrible rotten smell. As they travel it gets stronger and stronger forcing them to cover their noses and mouth less they choke on the horrible smell. Stream full of dead fish. Spawning trout die in mass quantities after they spawn littering areas with dead fish dying and deteriorating in the sun.