Commonly, particularly amongst chaotes, the idea of a servitor, or a created spirit who acts as a slave for the magician is discussed. I have seen things ranging from what I would categorize as little more than a thought form, to things so complex as an egregore considered as simply servitors. For our purposes we will consider them as a well-defined entity separate from but dependent upon its creator, programmed with a servile nature.
There are two basic types of servitors, those which are one use, and those which endure to be used for more than one task.
The first of these is programmed to perform on task and given only the abilities and adaptability needed to perform that task. After that task it dissolves itself as per the intent and nature with which the magician has programmed it.
The second may either be programmed with an array of skills and be given the directive that it use all its skills to serve the magician to the best of its ability. This sort of servitor is useful in that you have a permanent servant that develops itself to better know and serve your will and it may develop its own skills more readily in order to serve you. The unfortunate aspect of this servitor is its lack of specialization. Because of this while it may be highly skilled depending upon the skill and complexity with which the magician designs it, it will have no natural area of expertise and will be spread thin as a spiritual jack of all trades. This sort of servitor functions best as a personal occult aid to the magician.
The other typical approach to the long-term servitor is that which is made to perform tasks within a certain field. The magician should first make a list of areas of influence which he would wish to have servitors effect. They may be as broad or narrow as the magician wishes, the more narrow the category the more specialized and focused the servitor, but along with this comes a lack of adaptability and limited usefulness for the servitor.
For example, a servitor who rules over things having to do with the mind may be too broad in the sense of what abilities it needs, but also refined enough to be useful in the many areas which fall under his domain. If you create a servitor to rule over dreams he has a range of things over which he may exert effect, and the magician has a more obvious structure around which to create the servitor's skill set. The servitor will have both a wide enough set of abilities to deal with various occurrences and a set area which it commonly deals with in order for it to develop familiarity which leads to skill. The magician may further refine a servitor so that it deals only with nightmares. This would be a particularly narrow category of influence.
The servitor may be designed to perfectly execute those things by which the will of the magician may be brought about, but it will have no use beyond those things and may be a servitor which the magician infrequently has need of. In this case it may be best to create a one-use servitor and further specify it to create nightmares in the dreams of a specific individual over a specific period. Then the magician might specialize the nature of the servitor so that it is something which would frighten the individual.
In the case of long-term servitors with such refined specialization, the magician may find the need to create an entire host of servitors, and occasionally employ them simply for the purpose of giving them practice so that their patterns do not diminish from lack of being called into use.
Lastly, with long-term servitors the magician should be sure that the will of the servitor is to serve the will of the magician, and while the servitor should be given adaptability it must be integral to the servitor's being that it does not betray the magician or violate his commands.
When creating the servitor the magician begins by creating a base pattern of energy which he will build and define into the servitor. He then charges this field with the specific characteristics of the servitor. This may be visualized in the creation of balls of energy, charged with the characteristics given to the servitor, being placed within a husk or form into which the base energy has been shaped. These characteristics should be the skill set of the servitor.
When giving the servitor its nature the key function of that nature should be that the servitor is driven to serve the will of the magician. Included in that should be that which the servitor rules over. Additionally the magician may program into the servitor a limited adaptability and a quality that allows the servitor to learn from situations and obtain new skills which will benefit it in its work.
In doing this a personality may be given to the servitor, particularly in the case of complex long-term multitasking servitors. Often it is best to model the personality after that of the magician, creating a duplicate energy pattern based on the magicians, removing qualities which the servitor should not have, and then grafting it onto the servitor.
In solidifying the nature of the servitor, there should be two maps of its being. Its name, and its sigil. Create the name of the servitor so that it represents and contains all of the components of the servitor. The sigil of the servitor should be considered as a physical image representation of the energy pattern of the servitor. The creation of the sigil and the pronunciation of the name define the servitor against the undefined and bind its components into a singular pattern. The magician may charge the servitor to answer to a bastardized form of its name and to be summoned and respectful to a seal created from the bastardized name and an altered version of the sigil. This will allow the magician to pass use of his servitor while retaining the ultimate keys to its control as his own secret.
The final step of creating the servitor is the evocation of the servitor into being. The servitor only has adjunct being, in that the servitor's existence is dependent upon the magician giving it existence. It must be called forth from non-existence by the magician in a ritual evocation. The evocation should culminate with the vibration of the servitors name; vibrating it repeatedly to add strength to the definition of the servitor. The sigil may be drawn at this time as well, symbolizing the servitor being brought into being in the universe, and being defined against the undefined.
The magician should never neglect his servitors. He must provide for them some basis of being, and he must occasionally call them forth to be used in order to redefine their being lest they diverge from their programming or their pattern develops a dissonance from its exposure to other influences leading to the servitor becoming undefined and therefore useless.