Altana is an energy source used in the Gintama setting. It greatly influenced the universe and is behind the actions of some of the characters in this setting. It is a planet's life force itself.
Millennia before the start of this series, the Amanto discovered Altana and learned to convert it to usable energy. This could be used to create advanced technology, including faster than light spaceships and laser weapons. Unfortunately, an almost universe-spanning war for this resource resulted, causing lots of death and destruction. The war ended some time after when the survivors decided to sign a non-aggression pact and form an independent third party that would monitor Altana usage. The organization, the Altana Preservation Society, had wealthy Amanto as its members and were in charge of some planets' Altana Gates, a gate that covers an natural opening, or Hole, that a planet's Altana leaks out of. Thanks to being given free reign, the Society became a power unto themselves, later change their name to the Tendoushuu, conduct research into Altana and start conquering other planets for their Altana, earning the other Amanto's distrust of them. The planet Earth will be their latest conquest.
In Japan, Altana goes by the name Ryuumyakyu (Dragon Veins), with its hole in Edo protected by a clan of priestesses and their kami companions called the inugami. With the Amanto invasion, the recent generation of priestesses and inugami were deposed and the control of Earth's Altana Hole given to the Tendoushuu.
Unlimited Energy: Altana is the backbone for much of the Amanto's advanced technology. It is the main power behind all space ships and all planets' terminals, airport towers that sit on top of each Altana gate.
Crystallization: Altana has the ability to solidify into a rock that contains energy. These rocks are known to be so rare that only one or two crystals can be found in a planet's lifetime.
Rejuvenation/Regeneration: The knowledge that Altana gives beneficial properties to living things was widely known in the universe. This includes curing illnesses, restoring youth, granting vitality, etc. The Tendoushuu were researching how to use the Altana to grant anyone complete immortality.
- It is revealed during the Rakuyou Decisive Battle Arc that the Altana had succeeded in granting said immortality to two known people: Kouka and Utsuro. Yet their long lived, regenerative abilities were due to their bodies' mutation granting them the ability to absorb and store large amounts of their birth planet's energy. If they leave their birth planet, their Altana reserves will run out, reverting them to a normal person, probably even kill them as was the case with Kouka.