Board Thread:Questions and Answers/@comment-6935068-20130709051919/@comment-8986886-20130711010958

Hi there, Joker. I'll try to sort things out for you.


 * Reishi is the building material that everything in the spirit realms are made of, including human souls. It also exists in the human world in lesser quantities and is utilized by Quincy to create spirit weapons.


 * Reiryoku is the raw spiritual power a soul possesses. Humans with high Reiryoku are more sensitive to the spiritual world and can sometimes see spirits of the dead; both plusses and Hollows. In Toshiro Hitsugaya's case, prior to him becoming a Shinigami, his vast amount of Reiryoku even affected his grandmother by freezing the surrounding air.


 * Reiatsu is the pressure, or the physical manifestation of Reiryoku, which is achieved through control. Shinigami learn to control their Reiryoku at the Shin'o Academy. Reiatsu is used both in defence; Aizen negating Sui Feng's Suzumebachi, as well as offense; Ichigo's Getsuga Tensho. Someone with high Reiatsu can easily overwhelm individuals with lesser Reiatsu, making it difficult for them to move, or even breathe.

I hope that explains things. :)