A volume of character/relationship growth and development + a deeper look at our overarching villain and the developing plot.
The first half works better, encapsulating all that development within the story of another face-off between Inuyasha and Sesshomaru while the back-half has some villain monologuing and exposition from Kaede to explain Naraku/Onigumo's backstory. And it kind of feels like a shame that so much is explained so soon after Naraku's introduction? I think it would have worked better or at least been more fun if there remained more mystery around him.
Regardless, the return of Sesshomaru and the subsequent character growth is very good. Through the fight we also learn more about Tetsusaiga, the all-knowing and seeing puppet-master aspects of Naraku, and Kagome's growing spiritual powers.
Now that we've been introduced to Inuyasha's guilt over Kikyo and how heavily it weighs on him, it is taken to new heights as he becomes more serious about his actions and their effects. Up to this point we've seen him protect Kagome over and over again, but here there is more to it. It's emphasized. Not only can we recognize what's happening but Inuyasha can too. And so can "You're quicker when defending your wench" Sesshomaru. After what happened with Kikyo, Inuyasha has an increased need to protect Kagome and her getting hurt during his fight with Sesshomaru really fuels him with rage ("You shouldn't have involved Kagome...")
And while Inuyasha's new goal is to avenge Kikyo, within that is protecting Kagome from the same fate. This is made very clear multiple times. He tells Miroku to only do "one thing. Just don't let Kagome die" and later, in response to Shippo asking if he cares about ever seeing Kagome again, he says: "as long as I know she's alive somewhere, that's enough. I don't want to see another woman die" (because of me). This is a big change of pace from the Inuyasha of previous chapters/arcs, the one who hated when Kagome returned to her own time and prioritized her being in his era. He has gone from calling his era their home to saying beyond the well is "Kagome's true home." Previously he justified wanting Kagome there as being solely for the benefit of using her jewel detection powers (even though it was clear he also enjoyed her company), and now he is willing to forego the use of her abilities in order to prioritize her safety. The stakes have increased, but I think Inuyasha has evolved a little too.
The prioritization of Kagome's safety takes a toll in more ways than one, and we really see Inuyasha pushed to his limit. Not only does he get longer lasting injuries, but his desire to protect Kagome is so strong that he is able to defend her even when unconscious ("Inuyasha may seem unconscious...but if I should step too close...I know he will swing that blade.") We get some of Inuyasha's feelings on the matter in a slight disguise when he explains he sent Kagome home because "[he] can't fight the way [he wants] when she's around." Yes, his short-term goal of winning a fight and his actions may be altered by Kagome's presence and his main goal of protecting her, but the fight against Sesshomaru also shows that Kagome makes him a stronger and a more skilled fighter. His removal of Kagome from a dangerous environment does keep her safe, but it may be more about protecting his own feelings and emotional state.
Inuyasha isn't the only one who puts saving someone else first as Kagome does the same for him, constantly putting herself in the line of fire to help him out. She puts his needs above her own; they both are willing to endanger and sacrifice themselves for the other. Only Inuyasha might feel the reality of the danger more acutely because of what happened with Kikyo and how he is more durable than a human like Kagome.
The increased weight of danger and Inuyasha's growth really manifests in how we talks to Kagome before forcing her to go home. Though Kagome insists she isn't afraid, Inuyasha tells her: "I was scared." 'When I thought Kagome could die...I was scared.'" And really, Kagome should have more concerns about her own well-being. This is not a case of Kagome is right and Inuyasha is wrong. But Inuyasha gives off some mixed signals and is willing to be "the bad guy," going from hugging her to pushing her down the well and stealing the jewel. It is a sort of reflection of the perceived betrayal of Kikyo by Inuyasha–"pretending" to have affection for her just so he can take the jewel and acquire power when really he is acting this way because of his affection. There is something to be said about how the element of time is what saves Kagome from the same tragic fate as Kikyo...
Speaking of Kikyo and Inuyasha, learning more about Naraku and his history with Kikyo sets up another dynamic exploring hate/love. There are parallels between Inuyasha and Naraku.
And while Inuyasha, Miroku, and Shippo get more Naraku/Onigumo backstory, there is a pleasant teenage girl-ness to Kagome's experience on the other side of the well. But her distracted thoughts about Inuyasha also serve to illustrate how she is prioritizing his time over her own.
Overall, a solid volume that continues the overarching plot while developing the characters. Inuyasha gets his own gold star for trying to communicate, even if he ends up failing. This one is really only held back by some of the exposition. Sesshomaru always seems to bring some good stuff, working well as a vessel for story and development.