Pearl is a draconequus-unicorn hybrid (a uniquus), the daughter of Rarity and Discord, by means of an unsolicited encounter after the latter’s escape. While she considers herself to be a worthy heir to the “Lord/Lady of Chaos” title, her magic isn’t much stronger than an ordinary unicorn, and her reign of chaos consists of opening cereal boxes from the wrong end and mixing Skittles into the M&M bowl. Her name is a tongue-in-cheek reference the treasure that grows when foreign contaminants are left on the inside of a clam, so she often prefers to go by Lady Entropy, though this is a name that no one else actually calls her by.
 
Her cutie mark is two six-sided dice, one made of diamond and the other made of coal, both having rolled a seven. This represents her special talent, which is control over different forms of randomness, mainly entropy and probability. The former consists of an entropic beam she fires from her antler and a negentropic beam she fires from her horn; taken together, they allow her to increase and decrease the entropy of the target, in the form of tidiness, decay, temperature/phase change, et cetera. While she didn’t inherit her father’s immortality, she can use this ability to maintain a form of artificial agelessness, as she undoes any damage to her cells that may accumulate over time. Her probability control is more of a passive ability; in her immediate vicinity, things tend to go her way, with things she wants to happen being more likely to happen and things she doesn’t want to happen being less likely to happen, though this only applies to random events, and is not a guarantee.
 
As a result of her origins, she has developed a simmering disdain for rules and laws in general, resenting the fact that, technically, she “shouldn’t” ever have been created in the first place. Connecting to this, she has almost no respect for authority, especially authority over her, and hates being told what she can and cannot do.
 
One thing she actually is incapable of doing, however, is having spawn of her own. As is common for hybrid species, a mismatch of her chromosomes prevents her from producing viable ova. While she doesn’t actually want the responsibility of being a mother, she still views this as a personal flaw, which conflicts with her significant ego. By contrast, her digestive system works exceptionally well (digestion, after all, being a controlled increase in entropy), her omnivorous predilection having become obvious during her gestation when Rarity had to resort to eating clam chowder with digestive enzymes to satisfy her growing cravings. Pearl’s diet consists of more or less anything that any other species may eat, including hay, fruit, meat, and gemstones.