Byakuya of the Dreams was the last of Naraku's incarnations, and the only one who was loyal to him in the end. He first appeared in chapter 398 of the Inuyasha manga and episode 4 of Inuyasha: The Final Act, and while he didn't engage in combat, he acted as a spy and informant to Naraku.
He is voiced by Mitsuaki Madono in the Japanese version of the anime and Michael Adamthwaite in the English version, the latter of whom also voices Ginji Matsuzaki.
While completely loyal to Naraku, Byakuya was quite affable and polite, and insisted that others do the same. His appearance is very effeminate, and he was also shown to be somewhat sympathetic, expressing pity at Kanna's death.
Powers and Abilities
Flight - Similar to Kagura's feather, Byakuya used an origami swan as transportation.
Spying - Byakuya had the ability to detach his left eye to spy on Naraku's enemies from a distance.
Sword - Never used it in combat, but instead used it in the final battle against Naraku to capture Inuyasha's Meido Zangetsuha, in order to cut Kagome with it and trap her in the Shikon Jewel.