From Compendium of Worldly Lore
What is a Thrall?
Thralls are subservient living vessels of an enchantment caster's command. They are shells of what they once were living in complete obedience to the thrall-maker. They are the result of what happens when a creature's mind has been so shattered by the enchanter that it simply cannot mend on its own. The process of making such a creature can be done by any spellcaster with the Spell Focus (Enchantment) feat. Making a thrall is not a good act, nor can it really be done for good reasons. Breaking a creature's will in such a way is tantamount to extended and vicious torture. If you were good, at best you will become neutral and at worst your GM will shunt you to evil, with all penalties that that would entail.
An enchanter must tread carefully when making a thrall, as physical types are likely to have lower will saves and will be easier to break but pose grave danger to the enchanter should they mess up the process. Mage and Priest thralls would also be tempting but they have high saves, although if you take away their ability to cast they are all but helpless. Failure during any step releases the potential thrall from the effects of that step and the enchanter has to try it again. These setbacks can add days, weeks, and significant financial cost to the process.
Snaring the Mind
The creation of a thrall begins with a single spell. The enchanter must cast any compulsion designator spell that allows a saving throw on a target benefiting from its full Will Save bonus. If the target is immune to mind-affecting spells, that defense can (and must) be removed, but the target must have an unimpaired Will save and fail to resist this first spell. This initial failed save sets up the potential thrall's mind for the sensation of losing control that is vital to its ultimate surrender. The victim is now vulnerable, but the enchanter must move quickly, or the opportunity is lost. At any point during the duration of the compulsion, the enchanter must cast any charm designator spell that engenders friendship on the target and defeat its full Will save.
Again, it is important that the target has the benefit of an unimpeded saving throw. Breaking the targets willpower while it is at its strongest demonstrates the enchanter's superiority and puts him in a dominating position. Before the charm spell ends, the enchanter must now have the target accompany him alone to where the rest of the process will take place. Travelling with the enchanter is a decision the target will go with the enchanter, but the enchanter cannot use any further magic to force the target to comply. Use of Bluff or other skills is perfectly acceptable, however.
Once the target has returned with the enchanter, the capture stage is nearly complete. One final act is required. The enchanter must maneuver the target into some form of containment, such as into a cage or restraints. Even something as crude as grappling and forcing the victim into bondage will work. Once restrained the target must be freed of any enchantment spell affecting it, even the spells the enchantment did not cast. The victim's mind must be completely free of magical interference before the enchanter can proceed. This mental release brings with it sudden feelings of betrayal and vulnerability. The target has been lef into captivity by someone he viewed as a friend. Shock and anger are natural results of this betrayal and, unfortunately for the target, exactly what the enchanter needs him to feel. The capture is complete; the domination can begin.
Twisting the Will
Capturing the body of the target was the easy part. Now comes the truly difficult step, breaking down his thoughts and emotions until all that remains is his purest, most vulnerable self. This can take days, weeks, even months but, if the enchanter remains focused and the target cannot escape, success is nearly assured. Eventually, even the most rigid steel will bend. The enchanter must spend at least eight hours in the immediate company of the target. How this time is spent is up to the individual enchanter, but the basic process is always the same. During these eight hours, the enchanter must cast enchantment spells at the target in an attempt to wear down his resolve. Unlike the limitations of the capture stage, the target's Will save bonus need not be sacrosanct. The enchanter can use any means at his disposal to reduce it to a minimum of a third its full base score. The target must be left with enough Will to break, or the process cannot succeed. Thus, if a victim has a +9 base Will saving throw bonus, the enchanter can use spells, poison, or trauma to drop it to a minimum of +3. Any lower and the domination stage must begin again. The spells cast must alternate between charms and compulsions. Once the victim fails a save against a charm, the enchanter must switch to compulsion spells until the victim fails a save against one. Then the enchanter switches back and the series repeats.
The goal of this stage is to get the victim to fail his save three times in a row. Each time this happens the enchanter gets a hook into the target's mind. The enchanter is seeking to get three suck hooks, and this stage continues until this occurs. Any number of successful saves can be made between these triple failures but, once a hook happens it remains with the victim. Even if the target escapes captivity, each hook is considered a permanent compulsion effect that cannot be dispelled. In game terms each hook is a penalty the target suffers against any enchantment spell cast by the enchanter that put it there. The hook penalty equals 1/3 of the target's base Will save. It is possible to have multiple hooks from different enchanters, however hooks are only cumulative only if they come from the same source and no more than three can accumulate this way. When an enchanter creates three hooks in the target, the domination stage is complete. There is no limit to how long this can take to achieve. All that remains is to force submission.