I watched episode 51 of Naruto (kid) and I noticed this jutsu. My question is how it works?
Every part of the explanation I am about to give has been directly taken from the unofficial Naruto wiki : https://naruto.fandom.com/wiki/Dead_Soul_Technique
The Dead Soul Technique is described as a type of chakra-enhanced surgery. You can see it as an advanced puppetry technique which entirely forgoes chakra threads. Let's take it step by step :
- Kabuto performs open-heart surgery to induce a pulse. Through unexplained means, Kabuto opens the thoracic cavity on a corpse. Then, he manages to jump-start the heart and create a continuous pulse. Maybe he's using a technological implement similar to a pacemaker ; perhaps does he use advanced chakra surgery techniques to recreate and maintain a pulse. Either way, the heart starts pumping blood again.
- Kabuto injects chakra within the corpse to control it from afar. In essence, this is a forbidden, unethical puppetry technique which manipulates bodies from the inside. If I had to guess the exact inner workings of the technique, I would say Kabuto injects chakra within the victim's bloodstream, and manipulates that chakra to use the victim as a puppet. Either way, Kabuto needs to stay close to the puppet to keep manipulating it. He has also been shown to stay still while controlling the corpse ; and he can only control one at a time, meaning this particular puppetry technique demands high concentration.
- Kabuto stitches the body back up and performs additionnal surgery as needed. Kabuto often performs cosmetic surgery to disguise the puppet. Likewise, he also suppresses its body odours through unknown means. Various chakra surgery techniques are most likely used during this process.