Perhaps Kurama has some hidden ability that allows it to manipulate matter at a fundamental level. Using this ability, it could assemble atoms and molecules to construct a new body for Naruto. This process might be tied to the Kekkei Genkai in the fanfic, where the unique genetic trait plays a role in how the body is formed and stabilized.
In the fanfic, it could be that Kurama and Naruto have a deep spiritual connection that enables this. Kurama, being a powerful and ancient being, may have the knowledge and power to manifest a new body for Naruto. It might start with Kurama entering Naruto's consciousness on a deeper level than ever before and then using its willpower and chakra to gradually build up a new physical form from within Naruto's own chakra network.
If you want the clearest chapter reference, go to Chapter 183. Early on, Seeing that he held a blue ball identical to Su Yinwan's, Jiang Yan...; later, the chapter leans on Yinwan, it seems we're destined to be partners," he said..
If you want the clearest chapter reference, go to Chapter 154. Early on, Hahaha, I'm dying of laughter, Lili, do you really have to be so blunt?"...; later, the chapter leans on His expression is killing me!!!" "Help, she's making a scene, he's....
Chapter 183 is the strongest chapter-level answer because it starts from Seeing that he held a blue ball identical to Su Yinwan's, Jiang Yan... and follows through on Hadn't this woman been relentlessly pursuing him before?.
The best chapter pointer here is Chapter 188, "First in Grade, It Can Only Be Me, Jiang Cheng". It opens with With a "snap," the pencil Jiang Cheng was using to draw broke on the paper. and closes on I haven't even said anything yet, Zhou, why so nervous?.
Look to Chapter 138 for the clearest answer. It begins with Is there such a good deal?, keeps building through Qi Tianyu quickly nodded in agreement and knelt down to start helping..., and lands on Could it be that the poison also had a side effect of making a person more....
Chapter 192 is the strongest chapter-level answer because it starts from Jiang Shixu had never imagined that Jiang Cheng, who had been so arrogant... and follows through on Jiang Li responded with a detached "hmm" from the other end..
A practical answer is Chapter 172, because it turns the idea into a concrete scene. The chapter opens with Not only Shu Yan, but the entire internet was shocked when they saw Su..., adds pressure through It seems Director Sun kept it quite tight-lipped., and ends on Where's the chaotic scene I was.
A practical answer is Chapter 173, because it turns the idea into a concrete scene. The chapter opens with Jiang Li finally rose from her seat., adds pressure through Who knows how tough he plays behind the scenes;
Chapter 190 is the strongest chapter-level answer because it starts from Several people who didn't understand fell silent. and follows through on Because he saw the pack of cigarettes pinched between Jiang Li's fingers..
If you want the clearest chapter reference, go to Chapter 167. Early on, By the experimental field, Qi Tianyu was quite helpless as he watched Wen...; later, the chapter leans on He tried once again to pull back his suitcase, but to no avail, as one end....