There are and have been at least 8 bands called Sepia out there:
1) the succession-band of Mantus from Germany playing Goth-Rock,
2) an Indie Rock band from Switzerland
3) a R&B/Nu-Jazz-band from New York/USA
4) a House/Electronic-project from Italy(?).
5) an Indie Rock quartet from Baltimore, MD.
6) an Indie Rock band from Thailand
7) Sepiamusic
8) a touhou arranger from Sound-Nature doujin circle
9) Dubstep artist from Isle of Wight, UK. https://soundcloud.com/sepiamusicuk

Seemingly Sepia #3, #4 and #6 are not active anymore.

For further information:
1) http://www.sepia-music.com
2) http://www.sepiaworld.ch
4) http://www.epitonic.com/artists/sepia.html
5) http://www.sepiaband.com
6) Sepia Thailand Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.