Tsuki and Taiyo

Tsuki (the Dragon) is the Spirit Guardian of the Moon, and Taiyo (the Phoenix) is the Spirit Guardian of the Sun. In Chinese mythology the Dragon and Phoenix were considered like brother and sister, Yin and Yang, the Dragon represented the Emperor and the Phoenix represented the Empress. The Dragon was considered to be the dominate of the two, however the Chinese dragon is associated with the element water which is recessive to the Phoenix's element Fire, so they balance each other out, plus Fire and Water make sense with these two since the Sun is a great big ball of....well actually it's Plasma but it's Fire-like, and the Moon controls the tides.