Gods of Ragnarok

The Gods of Ragnarok, composed of Father Ragnarok, Mother Ragnarok and a Little Girl, were three Old Ones resembling stone statues who made sentient beings suffer to entertain themselves. They were named by Rassilon the gods Raag, Nah and Rok, (PROSE: Divided Loyalties) and referred to singularly as Ragnarok by the Seventh Doctor. (AUDIO: Signs and Wonders)

Origins
Though they were often classed among the Great Old Ones, (PROSE: All-Consuming Fire, Divided Loyalties) the Gods' universe of origin was a matter of some contention. As recounted in The Record of Rassilon, when Rassilon classified the three Gods of Ragnarok among the "Great Old Ones", he was using the term to specifically refer to members of the earlier race of Time Lords who ruled the universe before his own who survived into the new universe in godlike forms. He believed the three — Raag, Nah and Rok — to have been responsible for the destruction of this universe, however, and speculated that they may actualy have destroyed "countless universes" before that one, including their true, long-lost world of origin. (PROSE: Divided Loyalties)

The quantum harvester, meanwhile, believed that the Gods of Ragnarok came from a reality home to various death gods who had invaded the Doctor's universe, including the Beast, (COMIC: Cindy, Cleo and the Magic Sketchbook, Old Girl) who claimed to have originated from before the Doctor's universe. (TV: The Satan Pit)

In the Doctor's universe
They created the Land of Fiction as a pet project, but abandoned it shortly after. (PROSE: Conundrum)

They could manifest in different time-phases simultaneously, while they actually existed in their true time-space the Dark Circus, with a well on the planet Segonax actually leading to their realm. Additionally, they could create a multi-coloured portal to transport individuals to them. They could fire thunderbolts and reduce people to ashes accompanied by a clash of thunder and blinding light, and could also create rain. They used their eye symbol as a means to observe others, their actual eyes glowing green whenever they used their powers. Among other powers, they could reanimate dead bodies with their original persona intact and were able to sense events happening elsewhere.

They were known for taking people with individuality and imagination and wearing them down in their service, making them entertain the Gods endlessly, wanting something bigger and better with each act. The Doctor stated that he had fought the Gods of Ragnarok all through time. (TV: The Greatest Show in the Galaxy)

When tried to take away their power, they were able to overpower him, and kept him as a prisoner to amuse them. Using a talisman they gave him, who boosted his telepathic powers, the Master gathered the bunch of artists known as the Psychic Circus and brought them to the planet Segonax, meaning to use as both a source of entertainment for the Gods and a means to harness enough psychic power to escape from their grasp. This plan fell apart when Kingpin contacted the Seventh Doctor for help; he came and, exploiting the Gods' desire for fun, confronted the Master in front of them and eventually broke his connection to the Circus. He then left, abandoning the Master to the mercy of the Gods. (AUDIO: The Psychic Circus)

Later in their timeline, the Gods took over the Circus themselves, and charged the ringmaster and the chief clown with the task of keeping the others despite the desire to escape and luring spectators to their deaths. Outside their own world, they appeared as a man (referred to as "Father"), a woman (referred to as "Mother") and a little girl sitting in the audience. Their audience forms seemed to have some personality, the little girl complaining about being bored and the mother offering the Doctor popcorn. Their true stone forms, which had some degree of movement, were more adamant about having entertainment. Of course, by this point, their patience had been worn by the delays of the Psychic Circus getting more acts together.

Using the Circus as entertainment, the performers would wait for talent to arrive for competitions to possibly be a part of the Psychic Circus, trapping them in a cage until they would perform. The Gods had cards they would hold up to display a number relating to their reaction, "9" being great and "0" being the worst; a “0” would be followed by the performer(s) being reduced to ashes.

The Seventh Doctor travelled into their realm where he performed a magic show to appease them and then used a mirror amulet with their symbol to reflect their own power against them. The stone forms of the Gods broke apart and the Psychic Circus exploded and collapsed, breaking the Gods' link to the normal universe. (TV: The Greatest Show in the Galaxy)

One of the Gods was released from the Circle of Transcendence by Sutekh. It was frozen by the Tenth Doctor using a time dilation augmentor. It was later freed again and attacked Sutekh, who then killed it. (COMIC: Old Girl)

Other references
Anthony Rupert Hemmings mentioned the "gods of Ragnarok" to the Doctor, though this was in relation to gods associated with Ragnarok and not the Old Ones themselves. (PROSE: Timewyrm: Revelation)

In the video game Happy Deathday, played by Izzy Sinclair on the Time-Space Visualiser, a God of Ragnarok was among a host of "every single enemy" that the Doctor had ever defeated, who were assembled by the Beige Guardian and pitted against the Doctor's first eight incarnations. (COMIC: Happy Deathday)

The Doctor recalled the Gods several times in his later travels. (AUDIO: Signs and Wonders, PROSE: Conundrum, All-Consuming Fire)

Harry Randall and Lola Luna included the Gods in their song about the Doctor:
 * "Who gives the monsters such a shock? Who likes the sidekick in a frock? Who foils the Gods of Ragnarok? The Doctor!" (AUDIO: The Magic Mousetrap)

Behind the scenes

 * The Gods of Ragnarok are mentioned in a deleted scene from The Infinite Quest, as one of the beings which ruled the universe during the Dark Times.
 * The Doctor comments to Father Ragnarok that the Gods are not interested in beginnings, only in endings.
 * The Gods of Ragnarok's name is from the Nordic, which is often misunderstood as the "End of the World" or Armageddon. While an important part of Ragnarök is a climactic and cataclysmic battle, it ultimately ends with the renewal of the world as new and fertile.
 * One translation of Ragnarök is "the End of the Gods"; thus, the Gods of Ragnarok are "the Gods of the End of the Gods".