The Inner Demon (Daemon interioris) is a monster that preys on many a hero by taunting them through the promise of various shiny, sparkly baubles that later turn out to be cheap imitations of the real thing (patent pending) or even mirages. It is well-known that each hero has his or her own weakness regarding which particular items catch their attention. Each hero selects their own personal trinkets, whatnots, and knick-knacks to acquire and collect over the years - thus the saying "one man's trash is another man's treasure". Although the name even includes the word "demons", it is important to note that they live in shadows just out of sight or your peripheral vision at all times.
Inner demons are fed every time your hero ignores a command, runs from a monster, procrastinates, or buys an item just because it is on sale. They also are known to seek out a meager existence by siphoning off the residue of stupidity that heroes often display. They can be quite cute and cuddly as long as you follow three simple rules: don't feed them breakfast after midnight, don't get them wet unless they have waited at least thirty minutes (to avoid leg cramps), and don't let them go out in the sun without sunscreen.
In order to kill an Inner demon, your hero must personally decide to do so. An act of complete selflessness will make the inner demon wilt away and die. Every friendly interaction will slowly diminish the strength of the inner demon and things like hugs will make the inner demon run into the corner and cower in fear. Encouragements make them cry, whereas punishments make them giggle. They are impossible to see and thus are considered a formidable foe. This pet is also capable of occasionally revealing interesting locations in dungeons.