Throughout the series
The Shinidamachū first appeared in Kikyō's second appearance following her resurrection by the demon sorceress Urasue. The Shinidamachū acted as servants whose primary purpose was to collect the souls of newly deceased women and bring them to Kikyō, who needed them to keep her undead body animated. She had also been seen using them as messengers, scouts (reconnaissance), and even transportation on various occasions.
Creation and Powers
They did not serve for fighting, as they were never seen doing so directly. Despite this, they seemed to be strong, as five of them could lift a person up and fly away with them. Additionally, they were seen to be able to bind and immobilize people. They could steal the souls of the living, as well, making that person their master's mindless slave. At one point in the series, Naraku attempted to kill Kikyō by summoning his own giant Shinidamachū and sending it flying across the sky collecting all of the dead souls in the area, including those within Kikyō herself. They were also shown to have the power of intangibility, as they once passed through the wooden walls of the hut to come to Inuyasha. They could also turn invisible when not in use and then reappear whenever their miko had use for them. They also had the power to enhance Kikyō's spiritual powers greatly by delivering souls to aid her. It also seemed that they could carry the souls they collected indefinitely, saving them until Kikyō needed them. They also didn't seem to necessarily have to hold on to souls to herd them, as there were several instances in which Kikyō had numerous souls floating around in her vicinity while "empty-handed" Shinidamachū flew lazily about in the area.
They behave somewhat emotionlessly, collecting souls for Kikyō and obeying her commands anytime without hesitation. They were also seen following Kikyō into Mount Hakurei's barrier even though it was killing them; indeed, she had to dismiss them for their own welfare. They have displayed some kinds of protective behaviors, such as when the giant Shinidamachū attacked Kikyō and several of them started attacking it by slamming their bodies into it, albeit uselessly. They were also seen trying to bring souls to Kikyō when she was injured/immobilized inside of Hakurei's barrier, with their repeated failed attempts giving off a sense of agitated desperation.
- Initially Kikyō is seen with numerous soul collectors. However, after Mount Hakurei, Kikyō is normally only accompanied by two. It's possible Kikyō can summon as many as she wishes or the numbers depend on her strength.