The use of the term "preternatural agency" here carries no further implication as to the nature of the agency spoken of as preternatural.

This is only a farther development of animistic belief.

The preternatural agency is not necessarily conceived to be a personal agent in the full sense, but it is an agency which partakes of the attributes of personality to the extent of somewhat arbitrarily influencing the outcome of any enterprise, and especially of any contest.

The pervading belief in the hamingia or gipta (gaefa, authna) which lends so much of color to the Icelandic sagas specifically, and to early Germanic folk-legends, is an illustration of this sense of an extra-physical propensity in the course of events.
In this expression or form of the belief the propensity is scarcely personified although to a varying extent an individuality is imputed to it; and this individuated propensity is sometimes conceived to yield to circumstances, commonly to circumstances of a spiritual or preternatural character.

A well-known and striking exemplification of the belief--in a fairly advanced stage of differentiation and involving an anthropomorphic personification of the preternatural agent appealed to--is afforded by the wager of battle.