This is where terms used in Tokyo Ravens are briefly explained.
Ema are small wooden plaques on which Shinto worshippers write their prayers and wishes. The ema are then left hanging up in the shrine, where the Kami receive them.
Spirits or gods
Literally means 'the way of Yin and Yang'. This term is used for traditional Japanese isoteric cosmology. It is a mixture of natural science and occultism.
Practitioners of Onmyodo. Onmyoji are specialists in magic and divination. Their court responsibilities ranged from tasks such as keeping track of calendar to mystical duties such as divination and protection of the capital from evil spirits. It is said that an onmyoji could also summon and control Shikigami.
Spirits controlled by an Onmyoji's mystical power. The core of the mystical power can be put into doll made out of paper or human bodies.