> How can a person create a demon? What kind of person do you need to be?
> I'm not interested in creating one. I just want to know how do you think it can be done.

From page 159 of "Creating Gods and Demons" by Eruza Sirhc and Garunya no Densetsu:

By far the easiest method of creating a demon is also the most problematic, if you happen to be the type of person that values your unique individuality. This method involves channeling all the evil in your soul to one specific energy well in your body (this can be any part of your body, although the heart is generally most effective in this type of operation), and expelling it all at once into the form of a new soul.

This soul will recognise you as its source, and indeed, its master, and while it shall do as it pleases when under no strict orders, it shall make certain no harm comes to you, and shall obey your every command.

The biggest disadvantage of this method, however, is that once you do this, you have no negativity, conflict, or destructive thought left in you. You become, in effect, an angel, with no desire to do anything but good wherever you are, and no wish to utilise this demon-slave now in your possession. This is seen by most demonologists as a "complete waste of time and resources", and is therefore not recommended. In fact, some creators of demons following this method have been known to destroy or imprison for all eternity these demons, in order to ensure no harm is wrought upon the world.

The most common method, perhaps, of creating a demon is the "claymould" method. With clay, you mould the demon into whatever shape you desire, and, carefully following the step-by-step instructions in Chapter 6 of our sister book, "Invoking Gods and Summoning Demons", you call the demon to inhabit your clay mould.

Care must be taken in following the instructions word for word, to ensure the demon can utilise this clay well, in the way in which you intended, or you could quite conceivably end up with a clay figurine that simply seems to stare at you in a really spooky way.
This method has the obvious disadvantage of the uncertainty of summoning demons. Despite your best efforts and explicit instructions, it is not difficult to attract the attention of a powerful demon with godlike powers and a will of its own to match. By binding such a demon into a clay figure, you may anger the demon, and it will almost certainly destroy you.

It should also be noted that this method is not actually "creating" a demon. While the form of the clay will certainly play a part in the actions and nature of the demon, one should always remember that all demons have their own distinct natures, and you should thus not go around boasting that this demon is your "very own creation"

If you are good with words, you may prefer our third alternative. Simply put, you create the demon as a character in a book, or series of books. It is important that you write this while in trance, invoking whichever god of creation you feel most comfortable with (see Chapter 5 of "Invoking Gods and Summoning Demons"), or you will have no hope of freeing the demon from the limits of your fantasy world, nor of it possessing a consciousness separate from your own.

Remember that this demon will take on any trait you give it, so it is thus important to ensure that the demon will recognise you as its master, and will on no account wish to bring harm to you, and will do everything you wish. Often, in the name of art, demon-creators have let these strict rules slip. The results have been disastrous, and these demon-creators no longer live to tell the tale. See Appendix 1 for a list of all possible mistakes and precautions.

There is a fourth way of creating demons. It is a long, arduous process however, involving decades or even centuries of dedication of climbing the spiritual ladder until you reach godhood. This method is by far the most unpredictable, however, and many potential demon-creators using this method have been scarred for life. We do not recommend it.