Shikigami Kooni

About
These spirits are not like proper human or animal sprirts as they inhabit stones and leaves (thus making them nature spirits), Yoh was seen training to summon one by his grandfater, however he failed. Yet his grandfather had effortlessly summon three of them at a footstep, meaning they arent hard to summon. However, because no other character is shown to use these besides Yoh's grandfater it seems they must take considerable training to master and to summon them to aid in fighting.

Oversouls and Attacks
By using a Shikigami summoning technique, which is his speciality, Yohmei can create and control any number of these small Over Souls using small leaves as their mediums. Yohmei almost constantly uses these, even outside of combat, to do small tasks like fetching items, holding the newspaper, and so forth. However, if he so wishes they can send verbal messages or even kill people, if they have sufficient numbers. These spirits don't appear to be particularly smart.-
 * Shikigami Kooni


 * Asakura Shiki Onmyō Jutsu - Hyaku Shikigami (Asakura Style Yin and Yang Technique - Hundred Shikigami Kooni) This is Yohmei's favoured technique which creates countless Shikigami Kooni, that he can then use to surround an opponent and attack them from all directions at once. Yohmei also had an unamed attack where he summoned three Shikigami Kooni and used them to attack Yoh and although this has no name we can presume that the attack is similar to Asakura Shiki Onmyō Jutsu just in a smaller amount.