|Rōmaji||In no Fukusei|
|Literal English||"Shadow Replica"|
|Other Name(s)||Shadow Replica|
The Yin Replication Technique, (陰の複製, "In no Fukusei") also fittingly called the Shadow Replica is a truly peculiar Genjutsu developed by the very same cultists that developed the base of Isamu's other peculiar technique, Izanami; it was found together with the former and albeit it was incomplete at the time - Isamu later managed to complete it by making use of his great skill in Genjutsu coupled with his unique gifts and unusually keen mind.
The Yin Replication is an odd technique in that it can only be utilized by those who are in harmony with their spiritual side, in essence - Yin: It has many requirements to use and is hard to learn, but is only actually useful if the caster has extensive knowledge of many types of Genjutsu, knowing how the art works and how other techniques work by extension: This is due to the fact that the Yin Replication technique is capable of duplicating any Genjutsu of which the caster has sufficient knowledge --- even Kekkei Genkai ones such as Tsukuyomi; the greater the knowledge the greater the power of the duplicated Genjutsu; the technique not only duplicates the effect of that technique though - it also duplicates the drawbacks and the chakra useage of the technique, it should however be noted that its more expensive to use the Yin Replication than the Genjutsu in question trough normal means so for this reason the caster usually only uses this to duplicate Kekkei Genkai.
Ever since he managed to use his considerable resources to get several copies of the Uchiha teachings and scrolls - he's been capable of using this technique to replicate extremely powerful Kekkei Genkai techniques such as Tsukuyomi and indeed even Izanagi; albeit he'd likely never use the latter unless it was completely nessecary for him to do so; he does however occassionally use Tsukuyomi by using this technique as a medium - he's even capable of doing so without suffering the drawbacks of blindness after extended useage; being capable of healing the damage trough his medical ninjutsu, provided that he hasn't used it more than once in a battle: Whenever Isamu makes use of this technique to cast a Sharingan-related Genjutsu his eyes momentarily take the form of a spectral Sharingan.