Re: origin of last name Deramus
As Mike C says, there are few English language books on the meaning of Japanese names. One which I can recommend to you, though (if you can find a copy of it somewhere) is *Shadowings* by Lafcadio Hearn -- the writer who pretty much introduced 19th century Japan to the western world. This book of Hearn's observations on Japanese culture was first published in 1900, and contains a very informative section on Japanese female names, with names lists and meanings.
-- Nanaea