|Basicially:||Humans who obtain Soul Reaper powers|
A Substitute Soul Reaper (also means "Shinigami Daikou") are humans who became Soul Reapers by obtaining another Soul Reaper's power, or by going through a much harder and riskier process to transform him/herself into one. Obtaining another Soul Reaper's power is done by thrusting his/her Zanpakuto into the person's chest who wants to obtain the power. However, the percentage of success is low. In the case of success, the person normally obtain around half of the Soul Reaper's power, and only temporarily. In Ichigo Kurosaki's case however, the whole power of the original Soul Reaper, Rukia Kuchiki was transferred into him, due to his enormous innate spiritual power.
This practice is forbidden by the Soul Society, as it can give birth to rogue Soul Reapers with great power, thereby it is only applied as a last resort measure.