First, there was Asatru, which meant, technically, “True to the Aesir”, or the Norse/Germanic Gods of sky and war and culture. They included Odin, Frigga, Heimdall, Baldur, Iduna, Bragi, and many others. Eventually, those whose religious practice concentrated on the Vanir – the second, more agricultural pantheon of Gods including Frey, Freya, Njord, and Nerthus – decided that they would be called Vanatru. Some time after that, Abby Helasdottir of New Zealand coined the term Rökkatru, for those whose primary focus was the third pantheon of underworld Gods. These include Hela, Loki, Angrboda, Sigyn, Fenris, Jormundgand, Narvi and Vali, Surt, Mordgud, and Mengloth, among others.
The concept of a World Tree is not limited to northern Europe. Many cultures around the world have world trees, and it is usually the job of the shaman or spirit-worker in that culture to travel from world to world. There are always at least three levels: heaven, earth, and underworld. Each are valued equally and have their own blessings and dangers. There are always spirits of sky, spirits of earth, spirits of the beloved ancestors and those who guard them. Norse cosmology grew from a preliterate culture that followed this pattern, and we follow the same idea. Three pantheons, all valuable, all necessary to the functioning of Yggdrasil.
Those who identify as Rökkatru do not see “dark” as bad, nor “underworld gods” as evil. We feel that this is a Christian concept that has infiltrated some modern interpretations of Norse cosmology, first through the Christians that wrote down (and tainted) the only sources we have of these myths, and second through the Christian upbringings of many converts to Northern religion. Other Neo-Pagan sects have already been down this road and come out the other side; they have learned that underworld Gods are to be honored and revered for many things. Death is not evil; it is part of life. So is rot and decay, and loss, and the passing of all things. So is chaos, so is randomness, so is the destructive parts of Nature that we humans find inconvenient. All these things are sacred and so are the Rökkr. Just as there are those dedicated to Hecate, or Kali, or Hades, or Ereshkigal, or Coyote, so are there those who are dedicated to Loki and Hela and the others.
Currently, at this time, Heathenry (reconstructionist Norse/Germanic religion) prefers to limit itself to worship of the Aesir and Vanir. Northern Tradition Pagans, however, believe that Gods are not divided into categories of “good” and “bad” Gods. They are all worthy of honor, and we honor all of them. Since there are already many lovely websites with information about Asatru and Vanatru but very little for Rökkatru, and since honoring all three pantheons instead of only two is part of what sets us apart, we have chosen to put up a small place of education about this third truth. Not all Northern Tradition Pagans are Rökkatru – they might just as often be dedicated to or favor Aesir or Vanir Gods – but they will all agree that it is good to see all the Gods honored, and have no issue with the followers of underworld Gods.