What is Reiki?!?

[Kyu1982]

Until now, no one knows what exactly Reiki is.
Oh! Great keeps adding things.
1st. Reiki is described as a weapon that increase Red feather family members' power from within. (from Shinn)
2nd, It also helps Dragon eye user to control their power. (Shinn and Aya form past).
3rd. Has power to break/ignore Red feather's power. For example, Maya cut Kagiroi Tetsuhito's skin and slice him half while he had skin that has similar density as iron.
4th. Can kill Souhaku who cannot be killed, or possibly he still cannot be killed even with Reiki, but screw Souhaku by messing his Kii or Souhaku loses his memory or something. simply, screw Souhaku in a very very bad way.
-----------------------------------------------------------------------------------------
Who made Reiki?
1. it was made by first man who created 12 main families in order to help families with Red feather power.

2. it was made by first 11 main faimilies' leaders who made it in order to stop Souhaku from what he was planning. Souhaku wanted to remake his father, but the others did not like the idea, Souhaku killed them and put their bodies in temple.

3. it was made by Natsume family in order to stop other main families and Kago souhaku. In the volume 15. when Inoue was doing some mojo on Nagi, there were 10 dead bodies of 1st leader of 12 main families. I think it does not include Sohaku because he is still alive and walking, and I think Natsume is one that is missing, but possibly the other missing one isn't Natsume but Nagi. only Oh great will tell the story.

4. possibly made by Takayanagi in order to stop Red feather to go insane.
Its main purpose might be killing Red feather who does not listen to them.

[kk1]

Until now, no one knows what exactly Reiki is.
Oh! Great keeps adding things.
1st. Reiki is described as a weapon that increase Red feather family members' power from within. (from Shinn)
2nd, It also helps Dragon eye user to control their power. (Shinn and Aya form past).
3rd. Has power to break/ignore Red feather's power. For example, Maya cut Kagiroi Tetsuhito's skin and slice him half while he had skin that has similar density as iron.
4th. Can kill Souhaku who cannot be killed, or possibly he still cannot be killed even with Reiki, but screw Souhaku by messing his Kii or Souhaku loses his memory or something. simply, screw Souhaku in a very very bad way.
-----------------------------------------------------------------------------------------
Who made Reiki?
1. it was made by first man who created 12 main families in order to help families with Red feather power.

2. it was made by first 11 main faimilies' leaders who made it in order to stop Souhaku from what he was planning. Souhaku wanted to remake his father, but the others did not like the idea, Souhaku killed them and put their bodies in temple.

3. it was made by Natsume family in order to stop other main families and Kago souhaku. In the volume 15. when Inoue was doing some mojo on Nagi, there were 10 dead bodies of 1st leader of 12 main families. I think it does not include Sohaku because he is still alive and walking, and I think Natsume is one that is missing, but possibly the other missing one isn't Natsume but Nagi. only Oh great will tell the story.

4. possibly made by Takayanagi in order to stop Red feather to go insane.
Its main purpose might be killing Red feather who does not listen to them.

1)Nope this is never said.
2)Yup.
3) That was not Reiki's power that was Aya's power channeled through Reiki.
4)We still don't know the effect it has on Souhaku only that he fears it.

Who made Reiki? Below is all we know so far.

It is first brought up in Volume 4 and described as "The ceremonial blade "Reiki". Jyukon Onmyou entrapped all of the power of evil Buddhist ceremonies in this single katana, a crystalization of "cursed technology"!!
Acting in response to the "power" of the person weilding it. Maybe it will cause rain, or maybe it will... drive the user on a killing spree. The effect is vastly influenced by the nature of the weilder." Maya than says for someone without any "power" (a red feather gate in this case) it's just a stupidly long katana and her father gave it to her(when she was 8 ) for this reason to be it's "scabbard".
In vol 5 Shin's ghost then tries to take it but Aya tells him she wants so she won't lose herself or hurt anyone with her power(like at the bowling alley fight). And Shin tells her "Reiki" will suck all the power out of you and then you will have to confront that power face to face, a confrontation he lost. In the fight with between Bunshichi and Shin, Bunshichi assumes Shin needs Reiki to use the dragon eye, but in vol 7 Fu Chi'en explains that Shin used Reiki to control his power other wise he would kill everyone in the rage his power sent him into.

I'm assuming Jyukon Onmyou is a fictional name and is probably refering to an Omyouji, which at one time is what I thought Souhaku was. So add to your theories that maybe he himself made it and that's why it can be used against him

[kk1]

In rereading the earlier volumes I noticed something weird I didn't before about Reiki, how did Maya get Reiki back from Dougen?
AmI forgetting something? At the end of vol 7 during the Shin Mitsuomi fight, Dougen has Reiki at his office tower. In vol 8 there is a sword in his office under the flying Phoenix symbol but this isn't Reiki since Mitsuomi breaks it when he punches his dad( who picked it up and is holding it). Then when Mastataka and his father are shown leaving, neither is carrying a sword.
So the question is how did Maya get it back to the Natsume residence? Since she knew where it was and had the only key, I'm assuming she put it there.
edit
Ahh nevermind, when Mitsuomi shows up after Emi tells him Aya has Reiki he asks "wasn't Reiki entrusted to you?" so he or Dougen must have given it to her, funny I never noticed that before.