This is the design for the "Three Principles" of Soul, Mind, Body.
It is bascially the holy symbol used for the followers of the Ancients. Each of the three principles has a source to power it (food for the body, thought for the mind, and growth for the soul), as well as two others to maintain it.
The Ancients themselves are native to the world known as Gaia (or our Earth) and are the overseers of the world they have created called Avalon. They guide their ruined planet through their Guardians whom represent one or more of the three principles. Depending on which they are given different responsibilities.
BladeWing for example is a Guardian of the Principle of Body, which designates him as a soldier. Guardians of the Mind are intellects and secret keepers, given the task of guarding powerful knowledge. Those of the Soul are leaders in many respects, to give clarity and direction.