There are several groups, at least 5, with the name "Fallen". 1)
Fallen is the extreme-doom solo project of Funeral's drummer Eek. The project was formed in '96. Fans of the old Funeral, old Cathedral, should check this out. In good old doom tradition, the songs are up to 18 minutes long. Very high quality Doom! 2)
Fallen is a melodic metalcore band from the Vilvoorde area (Belgium), playing since 2003 and drawing influence from 90's H8000 metalcore as well as modern day melodic metal.