Eluveitie, formed in 2002, is a Swiss band that plays melodic death metal interspersed with Celtic folk instruments and elements. It took me by surprise that the band was actually Swiss with the Celtic influences, but I don't claim to know much about European influences and cultural spread, so what the hell. The only thing I know is that this band is great.
Most folk metal bands are closer to black metal than other genres, not so in this case. Eluveitie has far more in common with groups like Dark Tranquillity and Amon Amarth than black metal bands.
The band uses traditional Celtic instrumentation mixed with their metal. For instance, various members play the bagpipes, the hurdy gurdy, bodhran, mandola, and pipes. The mix of these traditional influences sounds amazing next to the melodic death metal that makes up the majority of the band's sound. The lyrics are often done in the extinct language Gaulish to add to the traditional nature of the influences.
Thus far, I only own the album Slania, which to date is the band's best album. It's fast and extreme with moments of beauty and melody. The band will be releasing their new album in just a few days. Hopefully, I will be able to find it quickly.