Four Images
Mythology & Folklore
Known in Chinese as the Sì Xiàng (四象four images, in Japanese the "shishou"), which translates to "the four images" which are comprised of four animals representative of the cardinal directions. The animals include:
Alternatively known collectively as "The Four Guardians" or "The Four Gods", the animals trace their orgins back to early Chinese history (with the first references occuring during the Chinese Warring States Era of 453-221 BCE). Because the four images are associated with the four cardinal directions, the four seasons and four colors it should come as little surprise that they are also associated with the "gogyo" (五行)/the five elements) and certain celestial bodies. Because their are five elements and four deities, earth is often linked to the more infrequently mentioned Huanglong, the yellow dragon. However Huanglong does not have a Japanese counterpart (Koryu/Oryu the dragon is sometimes referenced as the closest Japanese counterpart).
Relevance to MAO
Thus far two of the four images has appeared in MAO in the form of shikigami. Mao has summoned Genbu the tortoise and the Otori clan of fire users has control of Suzaku the bird.