Akago is a young infant incarnation, capable of speaking fluently, that Naraku created while in Hakurei-Zan. Akago is the physical life force of Naraku planted within an incarnation, allowing Naraku to withstand otherwise fatal damage. Akago, much like Naraku, has a liking of ordering others around and watching from the background. Akago has the ability to peer into living beings' souls, with which he can manipulate and control by grabbing on to their inner darkness. Due to being created on a holy mountain, Akago can also erect barriers with which he can block and reflect yōkai energy.
Once Naraku receives news of the final shard of the Jewel of Four Souls being in the borderland between the worlds of the living and dead, Akago and Kagura half-kill priests and monks in order to peer into the borderland. This remains unsuccessful until a more powerful priest slices Akago in two during his final seconds of life. Akago's halves are split between Kagura and Kanna, Kanna's half reforming into Akago, while Kagura's half became Hakudōshi. Akago is then placed by Kanna and Kohaku into the care of a daimyō's wife, who Kanna led to believe was her own newborn child, the actual child having been a stillborn child. After Abi-Hime's birds attack the castle and Kohaku kills the daimyō's wife, Akago was taken into hiding again.
After some time, both Akago and Hakudōshi grow tired of being ordered around by Naraku. As Akago is Naraku's life force, becoming independent was all the two needed to do to make Naraku lose all power. Thus, Hakudōshi created Mōryōmaru to protect Akago and be a more powerful body for him. Akago later is merged inside of Mōryōmaru by Kanna to give Mōryōmaru a soul. After Mōryōmaru is merged back into Naraku, however, Akago is as well, thus destroying both of them.