There was no reason for Orochimaru to forget about such a convenient Forbidden Technique as Impure World Reincarnation.
As it happened, Impure World Reincarnation—a blasphemous, inhumane, and unethical technique that desecrated the dead—had been invented by the Forbidden Technique expert, the Second Hokage. Yet while he was alive, he had failed to prepare any defenses to prevent himself from being summoned after death. As the saying went, good and evil would eventually receive their due. Thus, whenever someone used Impure World Reincarnation in the future, the Second Hokage would always be among the dead being toyed with. You could say he had gotten exactly what he had asked for.
Strictly speaking, Impure World Reincarnation had three versions: the version developed by the Second Hokage while he was alive, which counted as the alpha version; the version Orochimaru had slightly improved based on the Second Hokage's work, which counted as the beta version; and finally, the new version Kabuto Yakushi had developed based on Orochimaru's version. Its changes included reducing the burden on the caster, increasing the level of control, and greatly expanding the number of reincarnated corpses. That counted as the public-release version.
For the past several years, Orochimaru's attention had been led around by Certain Feathered Person's words, so his research into Impure World Reincarnation was considerably behind that of the original timeline. As a result, there was no way he had mastered the technique to the point of large-scale, general use. In other words, using it would still place a considerable burden on him.
For Orochimaru, that risk was not impossible to bear. The problem was how to find the right balance... The First Hokage was undoubtedly the God of Shinobi, but if Orochimaru sealed his mind and reincarnated him merely as a walking corpse, he had reason