In any city, in any country, go to any bordello that you can get yourself to. If you can find the owner, notify him that you wish to see someone called the "Holder of Seduction". Should the mere vocalization of the name bring the feel of pleasure and fear to them, then you have come to the right place.
They will lead you to a door previously unnoticed in the bordello, and you will descend down a flight of stairs alone. The descent will take up to ten minutes, and you will notice that the area around you will seem to grow older. Not decay, but rather seem more dated in design. The steel railing will morph to wood, the drywall will become stone, and the stairs beneath you will seem to be carved from rock.
You will exit into a circular ring that seems to encompass a large cylindrical room. Should you turn around, the door you entered from will not be there. Several doors will line the inner side of the ring. You must enter the seventh from your starting position clockwise.
The interior of the room resembles a Satanic summoning chamber, and, as with most summoning chambers, a demonic presence will be felt. Ancient bones litter the ground, the walls are tinted red from millenia of bloodshed. A pentagram will be laid out in the center of the room, glowing with a fierce orange hue.
In a carved alcove you will find a book and a dagger. No matter what page you turn the book to, you will find a single incantation. Taking the dagger in your hand you must let the blood from your body in any way you choose while reciting the incantation over the pentagram.
Should the ritual fail, I cannot help you any longer. Let it suffice to say that the bones are most definitely the remnants of Seekers who failed the ritual. Should it succeed, however, a column of flame will erupt from the pentagram. When it fades, a being will appear. Depending on who you are exactly, this creature's appearance will change. It may take the shape of your worst enemy, or your best love, or mentor. Regardless, it will be male if you are attracted to males, and female if you are attracted to females.
No matter whose shape it takes, it will be very, very beautiful. Its nude body and succulent figure will taunt you with every glance. You must ignore these temptations, for submitting to the seduction of the Holder is a fate worse than death and greater than bliss itself. Pain, agony, joy, and pleasure will all meld into one feeling that will leave you paralyzed and unable to react as the being mates fiercely and passionately with you. And it will not stop until every ounce of your life force has been drained.
You may ask it only one question: "How does it tempt us?" The creature may answer, it may not. If it chooses not to recite the answer to you, you are not out of luck. The book will stay with you upon your return to Earth, and it will contain the answer. The dagger, however, will remain here, or to be precise, in the heart of the creature. As long as it is bound by its chains, it will not be able to harm you. Stab its heart, and release it from this plane of existence.
It will burn and scream a scream more terrible than any other cry in the history of the universe. Even if you are an experienced Seeker, the sound may still send chills through you. Once it has completed its death, the door behind you will swing open. Exit- but make sure to take the book with you.
That book is Object 180 of 538. With the instructions inside, you may summon this demon at will to fight beside you, but take care not to fall into its sexual temptations.