Lorelei is a germanic river spirit/ goddess from the river Rhine in Germany. The name "Lorelei" refers also to the rock at which is her court. She is a powerful river spirit that has worldwide worshipers. Lorelei and many of her court are similar to nymphs, but are actually an unusual form of elf. She presides at her court on Lorelei and is the queen of a Seelie court of the Rhine. She is powerful and benevolent and controls the powers of the river. She is known by some locals as "the maiden of the Rhine", and many know her as a fairy queen or mermaid. There has been some recent confusion as to people calling her the angel of death. This is because of the popular "spirit" comics and movies about an immortal ex police officer, in which she plays Lorelei the angel of death. The "angel of death" in Jewish folklore is called Azrael, and Lorelei hasn't had much to do as a psychopomp (a spirit who helps in the process of death in one form or an other). She is benevolent and will aid humans in their endeavors sometimes.
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"The Lorelei is both a rock on the Rhine River, located between Switzerland and the North Sea, and a legendary siren-like creature who lives on the rock and lures sailors to their death. The Lorelei has been the site of many accidents, as it marks the narrowest point in the river, which is difficult and treacherous to navigate due to a strong current and shallow river bed. These accidents are no doubt the inspiration for the legend of a maiden whose song and appearance distracts sailors from their course. The maiden known as Lorelei has her origin in German folklore, where she is often portrayed as a Nixe, a fish-tailed creature similar to the Greek idea of the siren. Legend has it that the Lorelei was once a human maiden who sat on the rock waiting for her lover to return. When he never showed up, she threw herself into the river in despair. Ever since, the Lorelei has sat on the rock combing her hair and singing plaintively, causing sailors to wreck their vessels upon the rocks in revenge for her lover's betrayal." ~http://www.wisegeek.com/what-is-the-lorelei.htm