Fiendish succubi commonly used their ethereal form to slip through walls to reach a mortal's bedside, and linger there as they slept. Here, they filled their victim's dreams with debauched scenes and whispered of forbidden pleasures, tempting them to indulge in dark desires, appetites, and taboos. The more the succubus did this in their dreams, the more vulnerable their victim became to temptation in the waking world. Eventually, the succubus entered the mortal realm directly, in a pleasing form previously seen only in the dreams, and befriended or seduced their victim, so they could influence them directly and indulge all their desires so they would perform evil deeds of their own free will. When the victim was utterly corrupted, such as by committing three betrayals of thought, word, and deed, their soul was in the grip of the succubus, without need of contract or pledge. For a more virtuous victim, this corruption might take longer, but their downfall was all the more rewarding for the succubus. Finally, the succubus slew their victim with a kiss, and the corrupted soul went down to the Lower Planes as their prize. The succubus actually avoided charming the victim if they could help it, as the mortal would not be responsible for their actions and not truly corrupted. Thus, charming was mostly used for self-defense. Similarly, their lethal kiss was only used as a final assault or a parting shot before they escaped.
Fiendish succubi could become ethereal by slipping into the Ethereal Plane. They could also magically charm a humanoid, in sight up to 30 feet (9.1 meters) away, and make them obey any command they gave them. The victim might resist, especially if made to perform a harmful or suicidal action. Resisting freed their mind for 24 hours, but failure kept them beholden to the succubus for a full day. The succubus could only have one charmed victim at a time; taking another would free the last one.
Succubi and incubi were known to serve demon lords like Graz'zt as advisors and consorts. Graz'zt never went anywhere without a retinue of six succubi, mariliths, or lamias and his servant Yattara commanded a small squad of fellow succubi who engaged in espionage and infiltration. However, it was the demon lord Malcanthet who was renowned as the "Queen of the Succubi"; lesser demon lords like Shami-Amourae and Lynkhab contested for her title without success. Malcanthet was served by countless incubi and succubi in her palace, and she birthed many deadly succubi daughters to Pazuzu. Succubi also served the demon lord Eltab in the Citadel of Conjurers, and in the army of the balor Ndulu. Some succubi, like Soneillon, the Queen of Whispers, were free agents working their own grand plots.
In the Year of the Dowager Lady, 726 DR, an army of demons called the Scaled Horde emerged from the western Rawlinswood and Forest of Lethyr and conquered the kingdom of Impiltur. Commanded by the balor Ndulu, they comprised mostly succubi and glabrezu. Among them was the succubus known as Soneillon, who engineered the fall of the Durlaven dynasty then reigned as consort of King Agrosh the Scaled, styling herself the Queen of Whispers. She escaped when Agrosh was slain three years later. In the Year of Visions, 731 DR, the paladin Sarshel Elethlim defeated Ndulu in the Citadel of Conjurers, ending the Fiend Wars, but the balor and his demon army escaped and dispersed. Over the next half-century, Ndulu regathered his succubi and glabrezu, with Soneillon serving him as his chief spy and favorite consort. Finally, in the Year of the Moaning Gorge, 786 DR, Soneillon disguised herself as Prince Nord's mistress, but he narrowly resisted being subverted to her will, and she was imprisoned. Afterward, Ndulu's demons clashed with the grandsons of King Sarshel, the Paladin Princes, who created a vortex portal that sucked all the demon horde back to the Abyss. In following years, the remaining fiends were hunted by King Nord. Soneillon escaped imprisonment and spent centuries sowing corruption and strife in Impiltur and Chondath. 2b1af7f3a8