|Family||Amaterasu Himiko (Mother)|
Sohaku Kago (Brother)
Iyo Natsume is an ancestor of the Natsume Family and is the one who created Reiki.
Iyo is the one that created Reiki by using her own Ki and then had it infused with her mother Amaterasu's Dragon's Gate. This gave Reiki its ability of neutralization. Besides that she also possesses the Dragon's Eyes. With her Dragon's Eyes along with Reiki she has been projecting herself into the future to help deal with the situation with her brother Sohaku Kago. She shows Aya glimpses into the past so she can understand what is going on in the present. Before she can help them deal the finishing blows to Sohaku in the present she is killed by him in the past.
As Maya, Mitsuomi, and Madoka go to rescues Souichiro and confront Sohaku, Iyo mappears to Aya. Uyo takes her away to show her events of the past. She shows her Makiko Nagi participating in one of Sohaku's experiments and the events leading to Tetsuhito receiving more powers. The vision is interrupted when Iyo calls Aya to assist her sister.
Feudal Japan ArcEdit
With Maya's fight concluded, Iyo takes Maya’s ki that she has stored up for two years to continues her "trip" with Aya. Aya doesn't want to continue, but Iyo insists that once she knows everything the two will merge and break the chains of fate. She takes Aya to Feudal Japan, to see her ancestor of the same name.
Iyo reveals Sohaku has the power to control death and is in fact centuries old. In the past he attempted to use the Red Wing Resonance Effect to awaken powers in people worldwide. Aya's ancestor was one of the group of four other 12 founding families sent to kill Sohaku to end the long war. With the assistance of Tokuan Shojo's shape shifting power, the group was hoping to infiltrate Osaka Castle and assassinate Sohaku. With the death of Myouun Kabane, the group plan changes to a more direct attack. During that attack Reiki was wielded by a pile of bugs that looks like Aya's ancestor (the Dragon's Eye and the Dragon's Pupil were still the same power, allowing the past Aya to create bug-assisted illusions). After the fake Aya's destruction, Reiki used its power to aid Tokuan. In the end Aya's ancestor fatally wounds Sohaku, but dies herself in the process. Iyo shows Aya how Sohaku manages to survive, gain a body, and forces his adversaries into a truce.
The "trip" sucks up the majority Aya’s ki and she can no longer sustain the visions. She is forced back into the present. Reiki for the time being has been placed alongside Maya's body in the hospital by Aya.