Doppelgänger

Doppelgänger (倍歩行者 (ドペルギャンガー), Dōperugyangā; German for "Double Walker") is a technique first demonstrated by  during the training of. It allows for the user to create clones of themselves using absorbed, often with such remarkable attention to detail that even exceptional warriors cannot tell the difference between the fake and the real thing.

Description
By crafting a collection of into the likeness of the user, a Quincy is able to create clones of themselves ranging from a handful to perhaps hundreds depending upon their level of skill and the amount of  the Quincy possesses. Novices are often able to execute this technique to serve as a means of deception, having the clone serve as a stationary decoy, while more adept Quincy can create the duplicates with a specific intention programmed into them. Depending on the Quincy user, these commands can be simple, with the user ordering their clones to tackle an opponent or to continuously fire arrows until their individual energy reserves wear out, while more skilled users can imbue more complex orders into their clones. For the most part, however, the clones created from Doppelgänger are short-lived, lasting for mere moments at a time. They are generally created to serve specific purposes before vanishing. The more skilled the user is at creating them, the more impossible it becomes to tell the difference between them and the original Quincy, even with the use of.

Advanced users are able to actually regain the reiryoku utilized for the clone once it dissipates, simply by reeling the energy back in as the reishi that created it returns to the atmosphere. It is here that a secondary function of the Doppelgänger is revealed. Anything the clone has experienced, including thoughts and memories, all return to the original Quincy, as those memories are "imprinted" onto the reiryoku used to create them. Novices are unable to reel their energy back and thus this function is lost on them, but for more advanced Quincy, this becomes a valuable means of both training and information collection. One can send their clones into battle to collect data on an opponent without risking harm to themselves, or could utilize clones to speed up training by multiplying the effect of practicing something by several times over.

When Doppelgänger is combined with, a Quincy is able to create clones that appear to be capable of independent action. They are also noted as lasting much longer than normal duplicates, due to the fact that a Quincy is unconsciously funneling a constant stream of reishi into their clone bodies through the Ransōtengai.

Behind the Scenes
As one can probably tell, this technique was based on the Shadow Clone Technique from the anime and manga series, Naruto.