Planet Zythera is a gas planet that is excessively hot. Touching metal in this mass of a gas planet would instantly give you a burn scar, it's enough heat to use as a power source or be used as a laser. However, the heat and gas on this planet could create an explosion powerful enough to destroy neighboring planets close to it. Thankfully, this gas planet has a vital factor that kept it from exploding.
Every once in a while, the gas planet would shoot gas out into space if there's too much of it. Blood red geysers come from within the planet and shoots through craters. This event is called: Blood Cleansing. The reason behind why the geysers are blood red is a mystery, but it is to believe that the planet's core is the cause of this.
The prison in this horrible environment was named after the Planet itself. It was originally built there by the U.D.S. (United Dynasty of Systems) after realizing that some of the prisons in its galaxy couldn't hold some of the most powerful criminals there is. However, this lead to an abuse of power by the owner of the prison. The U.D.S. couldn't bother to check on the prison since they had their own fair share of problems to handle. The prison had 1,000 levels in total, from lowest to highest, keeping even the most dangerous criminals in check.
In order to prevent the prison from getting filled with powerful criminals, the heartless owner made a month where Blood Geysers were more frequent and have the prisoners survive outside for 20 days. What's the danger you ask? Well that's another chapter for next time.