There are multiple artists on Last.fm listed as Gjallarhorn;

1) Gjallarhorn is a Finnish band that performs world music with roots in the folk music of Finland and Sweden. The band's music echoes the ancient folk music tradition of Scandinavia with medieval ballads, minuets, prayers in runo-metric chanting and ancient Icelandic rímur epics in a modern way. The group is named after the Gjallarhorn of Norse mythology.

Gjallarhorn was formed in 1994 on the west coast of Finland, in the Swedish speaking area, by Jenny Wilhelms, Christopher Öhman (viola, mandola) and Jacob Frankenhaeuser (didgeridoo). The band started as a trio but became a quartet with percussion in 1996. The band has been a quartet ever since.

The music of the band remains Swedish in character. Most of their repertoire is the acoustic folk music of these Swedish-speaking Finns, from the unique minuets and ballads that have only survived in Ostrobothnia, to the old traditional waltzes. The didgeridoo and sub-contrabass recorder offer an underlying drone, a technique shared by some other Nordic bands such as Garmarna. Also notable is their use of the hardanger fiddle and Jenny Wilhelms' kulning, a high-pitched, wordless vocal technique based on traditional Scandinavian cattle-herding calls.

2) Gjallarhorn is an Italian epic/Viking metal band, whose lyrical themes mainly deal with those of Ragnarok. They have only released one album, Nordheim (2005). Their style is somewhat reminiscent of Hammerheart-era Bathory, with slow epic songs performed with clean vocals. Three members of Gjallarhorn also play in the epic-metal band Doomsword.

3) Gjallarhorn is a black-metal band from Kherson, Ukraine.
Lyrical themes: Paganism, History
Members:
Onswar Vocals, Keyboards (2004-present), Drums (2008-2014, 2016-present)
Nameless Bass (2006-2009), Guitars, Vocals (backing) (2009-present), Vocals (2009-2014)
Doomor Guitars (2006-present), Vocals (backing) (2011-present)
Grimwar Bass (2014-present) Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.