Far down in Christian times the participle leikinn was used in a manner which points to something mythical as the original reason for its application. In Biskupas, (i. 464) it is said of a man that he was leikinn by some magic being (flagd). Of another person who sought solitude and talked with himself, it is said in Eyrbyggja (270) that he was believed to be leikinn. Ynglingatal gives us the mythical explanation of this word.
In its strophe about King Dyggve, who died from disease, this poem says (Yngling., ch. 20) that, as the lower world dis had chosen him, Loke's kinswoman came and made him leikinn (Allvald Yngva thjodar Loka mær um leikinn hefir). The person who became leikinn is accordingly visited by Loke's kinswoman, or, if others have had the same task to perform, by some being who resembled her, and who brought psychical or physical disease.
In our mythical records there is mention made of a giantess whose very name, Leikin, Leikn, is immediately connected with that activity which Loke's kinswoman—and she too is a giantess—exercises when she makes a person leikinn. Of this personal Leikin we get the following information in our old records:
1. She is, as stated, of giant race (Younger Edda, i. 552).
2. She has once fared badly at Thor's hands. He broke her leg (Leggi brauzt thu Leiknar—Skaldsk., ch. 4, after a song by Vetrlidi).
3. She is kveldrida. The original and mythological meaning of kveldrida is a horsewoman of torture or death (from kvelja, to torture, to kill). The meaning, a horsewoman of the night, is a misunderstanding. Compare Vigfusson's Dict., sub voce "Kveld."
4. The horse which this woman of torture and death rides is black, untamed, difficult to manage (styggr), and ugly-grown (ljótvaxinn). It drinks human blood, and is accompanied by other horses belonging to Leikin, black and bloodthirsty like it. (All this is stated by Hallfred Vandradaskald.)[13] Perhaps these loose horses are intended for those persons whom the horsewomen of torture causes to die from disease, and whom she is to conduct to the lower world.
Popular traditions have preserved for our times the remembrance of the "ugly-grown" horse, that is, of a three-legged horse, which on its appearance brings sickness, epidemics, and plagues. The Danish popular belief (Thiele i. 137, 138) knows this monster and the word Hel-horse has been preserved in the vocabulary of the Danish language. The diseases brought by the Hel-horse are extremely dangerous, but not always fatal. When they are not fatal the convalescent is regarded as having ransomed his life with that tribute of loss of strength and of torture which the disease caused him, and in a symbolic sense he has then "given death a bushel of oats" (that is, to its horse). According to popular belief in Slesvik (Arnkiel, i. 55; cp. J. Grimm, Deutsche Myth, 804), Hel rides in the time of a plague on a three-legged horse and kills people. Thus the ugly-grown horse is not forgotten in traditions from the heathen time.
Völuspa inform us that in the primal age of man, the sorceress Heid went from house to house and was a welcome guest with evil women, since she seid Leikin (sida means to practise sorcery). Now, as Leikin is the "horsewoman of torture and death," and rides the Hel-horse, then the expression sida Leikin can mean nothing else than by sorcery to send Leikin, the messenger of disease and death, to those persons who are the victims of the evil wishes of "evil women;" or, more abstractly, to bring by sorcery dangerous diseases to men.[14]