Board Thread:Questions and Answers/@comment-31283382-20131221170348/@comment-8986886-20131223114256

MilanVukas wrote: Reiatsu?

I'm not sure if you answered my question, or if you asked what Reiatsu meant, but Souls do not gain Reiryoku (spirit energy) when they become Shinigami. They become Shinigami  because  they have strong spiritual energy.

Reiatsu is Reiryoku that has been focused into a Zanpakutõ, Kidõ, or Shunpo etc; it's required for a Shinigami to perform any advanced technique.