I really like small familiaresque creatures like goblins, trolls, fairies, pixies, demons, etc.
In my universe, imps are attracted to people who have certain vices in their hearts and they favor addictive ones the most. Imps aren't necessarily evil but they have an affinity for malevolent feelings, deceptiveness, annoyance, anger, and many other emotions one would consider evil and feed off those feelings and especially deeds done while under the influence of those feelings. An imp who attaches themselves to someone will use their powers to inflame the host’s vices; they'll make you jealous, suspicious, paranoid, temperamental, addictive, and even annoying at times. They'll sometimes get even or make life miserable for those their "master" is at odds with in order to feed off those around their host as well but if their host can find the strength to resist the urges and negativity the imp craves they can find themselves at the receiving end of the imp's wrath.
Of all the things an imp craves its anger and gambling. Both are things that can potentially foster the most negativity. An imp can use its powers to make their host win at anything and vice versa. Someone with an imp accompanying them almost always has either a foul temper or a well hidden cruel streak about them. Loyalty is never a trait to expect from an imp since they are always out for themselves and as fast as they attach themselves to someone they have already thought of a hundreds ways to cruelly dump that person, usually in a situation with no hope like leaving them with staggering gambling debts or making them do something they regret out of anger.
It is said that the most powerful of imps, or a “grand imp” are the ones that are attached to objects for they can grant wishes to the object's owner but they must "loan" their soul in order to do so and if they die before they can willing pass that object to someone else the imp denies that person an afterlife and person's soul is now property of the imp and has to serve as their slave until someone bargains for that person’s soul at which time the person can either pass on or become the property of a new owner. But that’s all imp legend, of course. X3
