Sleigh Beggy (夜の愛し仔) Surei bega are a rare type of human with the the ability to both generate and absorb a large quantity of magical energy, the cost of having a shorter lifespan.
Sleigh Beggies are a type of human who have a natural affinity towards the fae and other supernatural entities, drawing their kind towards them unintentionally. Because their bodies naturally absorb magic but they typically lack the means of controlling it, they die fairly young and often to either physical or mental illness. This is why, despite the fact that there are more Sleigh Beggy than natural-born mages, their numbers are few and far between.
Sleigh Beggy are highly prized by both other sorcerers and fae. The former because their organs naturally absorb magic and so they can be used as batteries for magic and the latter because they are naturally drawn to them as they view Sleigh Beggy as being closer to their kind. This often brings them misfortune as well, because the fae drawn to them will act against their wishes, more so for those who are not gifted with the Sight and cannot see the fae. The fae's goodwill does not always result in the happiness and, when left to their own interpretation, their love and loyalty manifests into both luck and ill fortune. 
Sleigh Beggy unconsciously absorb a lot of magical energy, but lack the means of expressing it unless they are trained in magic or other methods. As a Sleigh Beggy draws attention from Fae, they will have little difficulty becoming mages if they find a mentor to train them and be capable of powerful magic. But magic beyond their means tires them easily and wears out their bodies to the point of exhaustion that lasts for several days, if not death.
- Please be aware that "Sleigh Beggy" is the official translation used by Seven Seas Entertainment and that the wiki won't be using the scanlator's version: "Slay Vega".
- The term "Sleigh Beggy" or rather "Sleih Beggey" in the Manx language, means "little people." (The equivalent of "fairy" in English.) is a term used to describe a type of fairy that originally inhabited the Isle of Man.