Avernus was the largest layer of Baator and one of the most traditionally infernal—a blasted hellscape in the most literal sense filled with rivers of lava, barren hills, and low, rocky mountains as far as the eye could see. To scale the mountains or move too quickly was unwise at best, since obsidian, quartz, and other crystals jutted from the jagged land, cutting clothes and slicing flesh. The ubiquitous presence of rocks and boulders, some of which seemed to resemble tormented faces and shapes of creatures, rendered the terrain extremely treacherous and difficult to cross at any pace quicker than a fast walk. Rubble covered the vast, ashen plains of Avernus's charred wastes. Fireballs raced across the dark sky of Avernus, seemingly at random (but on closer inspection actively targeted motion), and fell to the scorched earth, leaving smoking impact craters and burnt corpses in their wake. Travelers would need to find shelter, such as a building or cave, lest they inevitably be struck. The acrid air was clouded with pumice and volcanic ash from the foul fumaroles and blighted with flies.
Roiling clouds of red and black flickered with orange flames but the atmosphere had neither sun nor stars, only a constant, blood-red light in the thicker air. Blood, as it would happen, was the leitmotif of Avernus; it was where the River of Blood ran through Baator, collecting rivulets from every gulch, stream, and pool, from the victims of millions of battles. Practically all of the plane was bathed in a coat of blood and covered with bones and gore, whether devilish, demonic, or otherwise, acting as a grim reminder of the regular bloodshed that marked an average day in Avernus. I was an incubus, Succubi and incubi inhabit all of the Lower Planes, and the lascivious dark-winged fiends can be found in service to devils, demons, night hags, rakshasas, and yugoloths. Asmodeus, ruler of the Nine Hells, uses these fiends to tempt mortals to perform evil acts. The demon lord Graz'zt keeps succubi and incubi as advisers and consorts. Though legend speaks of them separately, any succubus can become an incubus, and vice versa. Most of these fiends do have a preference for one form or the other.
Mortals only rarely see a succubus or incubus in its true form, however, for the fiend typically begins its moral corruption in veiled, insidious ways. A succubus or incubus first appears in ethereal form, passing through walls like a ghost to lurk next to a mortal's bedside and whisper forbidden pleasures. Sleeping victims are tempted to give in to their darkest desires, indulge in taboos, and feed forbidden appetites. As the fiend fills the victim's dreams with debauched images, the victim becomes more susceptible to temptation in everyday life. Inevitably, the fiend enters the mortal realm in tempting form to directly influence a creature's actions. Appearing in the guise of a humanoid who has previously appeared only in the victim's dreams, the succubus or incubus seduces or befriends its victim, indulging all its desires so that it performs evil acts of its own free will. A mortal bequeaths its soul to the fiend not by pledge or contract. Instead, when a succubus or incubus has corrupted a creature by causing victims to commit three betrayals: in thought, word, and deed-the soul belongs to the fiend.
The more virtuous the fiend's prey, the longer the corruption takes, but the more rewarding the downfall. After successfully corrupting a victim, the succubus or incubus kills it, and the tainted soul descends into the Lower Planes. The succubus or incubus resorts to charming a victim magically only when necessary, usually as a form of self-defense. A charmed creature isn't responsible for its actions, so forcing it to behave against its will won't bring the fiend closer to the ultimate prize: the victim's soul. I read this from the in-game encyclopedia. While that was all well and good, we were fiends that needed sustenance from humans. An incubus or succubus could take that sustenance either draining them of all their sexual energy in dreams or by physically fucking them in their world. I had black leather wings like a bat. They were high on my back and I knew that I could fly with them. Before I could take flight, someone called out to me. It was a group of NPCs. "Hey you! Come here. We're going to the human world. You whelps have to learn how to feed and use your powers correctly." one said.
