One of the most innovative new game mechanics Skirmisher introduced in our wildly popular OGL/d20 sourcebook Nuisances was the concept of the Defect. Followers of this site have probably seen that we we post new Defects on a regular basis, so I figured we were overdue in explaining to those who do not own that book or its expanded followup, Nuisances: Director's Cut, how to use these in a game. Following is a slightly updated version of the introduction to "Chapter 5: Defects" from Nuisances: Director's Cut, which explains what these are and how to use them in the game. This material also appears in our relatively new Jester Dragon's Guide to Defects. 

Even as characters can have Feats that give them particular aptitudes and enhance their various skills and abilities, so too can they suffer from Defects that negatively affect their ability to function. Characters can acquire Defects — whether temporarily or permanently — during the course of the game in a number of different ways, including the results of curses and side effects of double-edged magic items. 

There is no limit to the number of Defects a character can have (just look around a typical gaming convention for validation of this ruling). Most Defects be taken only once, but a number have effects that stack (e.g., Fugly) or that can be applied to different factors (e.g., Allergy, Phobia), as noted in the individual descriptions. 

Players can also opt to willingly give their characters Defects (e.g., in the interests of roleplaying and character development), either when their character is created or upon attaining a new level. Those who do so are entitled to take bonus Feats in exchange. While there is no limit to the number of Defects a character can have, there are some limitations on the number of offsetting bonus Feats a character can acquire, as follows:
     * The number of offsetting bonus must always be fewer than the regular number of Feats a character is entitled to (i.e., those that are acquired initially and every third level, and not including bonus feats acquired as a benefit of a class or race). The exception to this is if the character has one regular Feat, in which case he can still also have one offsetting Feat.
     * Offsetting Feats can only be acquired at levels other than those at which the character receives a regular level-based feat (althought the Defects could be acquired sooner). The exception to this is when the character is 1st level.
     * In all cases a character must meet the prerequisites of an offsetting bonus Feat in order to take it.

There also a number of Metamagic Defects that can profoundly affect the spells used by characters and have a dramatic influence on game play. Some of these allow as many as two or even three offsetting Feats. There is also at least one Item Creation Defect. 

If a character manages to free himself of a particular Defect after taking it in exchange for a Feat, (e.g., if a Fat character loses weight), he will subsequently lose the offsetting Feat as well, either the one he took in exchange for it or one of the DM's choosing. 

Effects of passive Defects (i.e., those that have an ongoing effect that does not generally need to be adjudicated) typically have effects equal in power to Feats. For example, the Feat Lightning Reflexes affects Reflex saves by +2 and the Defect Sluggish Reflexes affects them by -2. Effects of active Defects, however, which may only come up infrequently and which players may not be as quick to emphasize often have detrimental effects greater in power than the benefits typically bestowed by Feats. 

Unlike Feats, however, players cannot necessarily be expected to remember their Defects at inopportune times. This often pleasurable task must fall to the DM, and it is recommended that he keep a list of various characters' Defects handy, and refer to it periodically, so as not to miss any easy or appropriate opportunities to apply them. Ideally, any given player's Defects surface and have some impact — if only a comical one — at least once in each game session. 

Sometimes, at the DM's option, a particular Defect can be attributed to all the members of a race, tribe, or other grouping (e.g., the members of a particular subspecies of Dwarf might suffer from the Defect Magic Item Jinx).