[8] In the summer of 2010, sediments were analysed from a gravity core taken in the rift valley on the Knipovich ridge in the Arctic Ocean, near the Loki's Castle hydrothermal vent site.

Specific sediment horizons previously shown to contain high abundances of novel archaeal lineages were subjected to metagenomic analysis.

[9][10] In 2015, an Uppsala University-led team proposed the Lokiarchaeota phylum based on phylogenetic analyses using a set of highly conserved protein-coding genes.

[11] The group was named for the shape-shifting Norse god Loki, in an allusion to the hydrothermal vent complex from which the first genome sample originated.

[12] The Loki of mythology has been described as "a staggeringly complex, confusing, and ambivalent figure who has been the catalyst of countless unresolved scholarly controversies",[13] analogous to the role of Lokiarchaeota in the debates about the origin of eukaryotes.

[11][14] In 2016, a University of Texas-led team discovered Thorarchaeota from samples taken from the White Oak River in North Carolina, named in reference to Thor, another Norse god.

[15] Samples from Loki's Castle, Yellowstone National Park, Aarhus Bay, an aquifer near the Colorado River, New Zealand's Radiata Pool, hydrothermal vents near Taketomi Island, Japan, and the White Oak River estuary in the United States contained Odinarchaeota and Heimdallarchaeota;[3] following the Norse deity naming convention, these groups were named for Odin and Heimdall respectively.

Jordarchaeia Odinarchaeia Baldrarchaeia Lokiarchaeales Helarchaeales Thorarcheaia Hermodarcheaia Sifarchaeia Wukongarchaeia Njordarchaeales Gerdarchaeales Heimdallarchaeaceae Kariarchaeaceae Hodarchaeales

Thermoproteota (TACK) "Thorarchaeia" (MBG-B) "Njordarchaeia" "Odinarchaeia" "Freyrarchaeaceae" "Jordarchaeaceae" "Baldrarchaeia" "Hermodarchaeia" "Helarchaeales" "Sigynarchaeaceae" Promethearchaeaceae["Lokiarchaeaceae"] "Sifarchaeales" "Borrarchaeales" "Wukongarchaeia" "Hodarchaeales" "Gerdarchaeales" (JABLTI01) "Kariarchaeales" "Heimdallarchaeales" In the depicted scenario, the Eukaryota are deep in the tree of Promethearchaeati.

[40][41][42] The viruses were assigned to Lokiarchaeia, Thorarchaeia, Odinarchaeia and Helarchaeia hosts using CRISPR spacer matching to the corresponding protospacers within the viral genomes.

[44][40] In addition to viruses, several groups of cryptic mobile genetic elements have been discovered through CRISPR spacer matching to be associated with Promethearchaeati archaea of the Lokiarchaeia, Thorarchaeia and Heimdallarchaeota lineages.