I'll have to say yes. ^_^ It's called "The Twelve Treasures" series by Rosemary Edghill (alias for Eluki bes Shahar, who's written more in the sci-fi field) and there are three books, starting with "The Sword of Maiden's Tears". I've always been a fan of falling into another world stories, and these stories feature a young elf who goes and falls into New York City -- and promptly gets mugged and his magical sword is stolen. The people he winds up with don't believe a word he says, including the 30-year-old librarian who is apparently his [quasi-reluctant] soulmate: not about being an elf or about being from another world or about his magical sword having the power to turn humans into grendels.

Only he does, and he is, and it does. And then there's a grendel in the NYC subway system. XD