Hi, I really appreciate the depth you go into when you discuss Inuyasha questions. Your knowledge of the manga and anima really shows! I was wondering if you've ever thought about the inconsistencies in Naraku's powers, from the characters' backstories to the main storyline? If he has the power to curse wind tunnels onto generations, how come he only does it once? If he can take the form of anyone well enough to deceive a dog demon, how come he never does it again?
Thank you for the sweet message!
Unfortunately for me, who loves concrete rules when it comes to world building, Rumiko Takahashi just doesn't do that. Whatever magic systems are in her stories are just there to serve the characters, story and themes. That's usually why her characters will just develop whatever abilities she thinks are necessary for the plot. Or whatever she thinks will add interesting drama or comedy.
For Naraku it's also definitely a case of "he can't be too strong because Takahashi doesn't want to end the series yet" and "Takahashi kind of forgot because it's been 5 years since she wrote that chapter", lol. In one interview she did when the anime was released, she admitted to be surprised that Inuyasha and Kagome were so antagonistic to each other at the beginning because the first chapters were ~4 years ago for her. People have also noted that she seemed to ignore some of Kagome's previous feats, to make it seem as if Kagome required a power up later on. The whole "your powers were actually reduced from birth!" plot that she introduced toward the end of the series is funny when you consider the stuff that Kagome was doing early on in the story.
So yeah, the main reason is Rumiko Takahashi wanting to prolong her series, so she has to deliberately weaken her characters in order to keep them struggling. She just never want to stop working on manga so she'd rather stretch out her ongoing series than come up with a whole new one.
