This is an article to help elaborate upon and describe the different forms of afterlife in the OG42 universe, here to help you, the community, to better understand it a little better.
In the world of Osaka Gakuin, the Afterlife is very much a real thing. Reserved for any being with a soul, which is just about everyone that wasn't already born into a realm of Afterlife, and born or made artificially. So, in other words, naturally born Angels, naturally born Demons, Homunculi, and Androids have no real afterlife to speak of. Once they die, it's nothing.
The Afterlife one goes to depends largely on their own actions in life, as well as their own will. It is fully possible for someone with a soul to appear in no Afterlife once they die as well, for the same reasoning as the actions that they caused in life, being largely neutral, as well as not powerful enough to stay on the human realm as a Ghost.
While the Realms of Afterlife are breachable by some, being those set races born into it and are powerful enough to traverse between their realm and Earth, for most, the only way is to die. It is largely unheard of that someone who didn't die managed to go to a realm of Afterlife and then come back out alive still. They are realms of the dead, after all, and should stay that way.
The Realm of Afterlife for Angels, as well as those who committed great and helpful deeds in their life. Heaven is a place where those whose Faith never wavered or waned are granted peace in their transcendence. The Realm of Angles consist of Nine Heavens that separated into a Trinity Hierarchy: God's Confidants, The Court of Heaven, and The Ministry of Heaven. The Ministry of Heaven is where all those who have allowed themselves to pass on, go and live happily in eternity. Unless they wish to rise through the ranks of the Angel Hierarchy then they are allowed to collect Faith, but otherwise most Angels are usually content to live in the "Harmony" of Heaven.
For further information please refer to Angels for more details pertaining to Heaven's Society.
The Realm of Afterlife for Demons, as well as those who committed great sins and crime in their life, being dragged down to suffer for eternity as punishment. Unlike Heaven, Hell is split up into multiple sections, specifically, circles. These circles are split up into the well known Cardinal Sins, the first circle being Lust, than Gluttony, than Greed, than Sloth, than Wrath, than Envy, and finally the 7th circle as Pride. Sinners are separated into these 7 circles depending on what Sin has been committed, being made to suffer due to it. There is no specific torture for each Circle, the only thing that's mandated is that there be torture.
While those dragged down into Hell aren't taken there, there are 2 more Circles of Hell. For more information, going to the Demons page is recommended.
Souls of the living that managed to stay on the physical plane of Earth one way or the other, either through a cheat method, natural means, or sheer strength of will. However, for these Ghosts, they are not permitted to enter any Realm of Afterlife once they "die" again, or even while a Ghost.