Inuyasha the Movie 2: The Castle Beyond the Looking Glass

Miroku's Wind Tunnel was a curse placed on his family by Naraku. Once Naraku is defeated, the curse that created the Wind Tunnel is lifted, causing it to vanish from Miroku's hand. However, during the final battle against Kaguya, the Wind Tunnel returns, likely because the threat of Naraku's lingering influence resurfaces when he reveals himself again.

Kaguya requires five sacred treasures to fully manifest her power: the Robe of the Fire-Rat, a jade, a Buddhist relic, a golden pillar, and a silver bowl. These items are scattered across different locations, and Kagura and Kanna (Naraku's incarnations) are sent to retrieve them as part of the deal to free Kaguya from her mirror prison.

The heart-shaped locket contains Kagome's photo and represents her connection to Inuyasha. When Kaguya freezes time into eternal night, the locket acts as a protective talisman that keeps Inuyasha immune to the time freeze effect. The other heroes survive by using modern-era items from Kagome's first-aid kit, but Inuyasha's immunity comes specifically from wearing the locket she gave him.

Kagome offers Inuyasha the locket earlier in the film, which he initially seems to reject.

Kaguya deliberately transforms Inuyasha into a full demon as part of her strategy. She has the power to control demon transformations, and she forces Inuyasha into his fully demonic form to turn him into a more powerful but uncontrollable weapon. The transformation makes him lose his human reasoning and become a danger to everyone, including Kagome.

Kagome's kiss breaks Kaguya's spell over Inuyasha. The power of their emotional bond and Inuyasha's love for Kagome counteracts the demonic transformation magic that Kaguya imposed. After reverting, Inuyasha declares he will try to stay as half-demon longer for Kagome's sake, showing his commitment to maintaining his human heart.

The locket Kagome gives Inuyasha represents their deepening bond, which the kiss ultimately fulfills.

Kaguya is not actually the Princess of the Heavens she claims to be. She is a demon who absorbed the real Princess Kaguya and adopted her form and title. She uses the legend of the celestial princess as a facade to manipulate others into helping her gather the five items she needs to achieve her goal of eternal night.

Kagura suspects Kaguya isn't who she claims to be and attempts to strike her.

Naraku concealed himself inside Kohaku's body after being defeated, waiting silently for Kaguya to emerge. His plan was to wait for Kaguya to fully manifest her power, then absorb her to gain immortality. This explains how he survived his apparent defeat and why he reappears at the climax of the movie.

When Kaguya freezes time into eternal night, most people become frozen. The group survives by using items from Kagome's first-aid kit that originated from the modern era, which seem to exist outside the frozen time domain. These items provide enough protection for most of the team, while Inuyasha is specifically protected by Kagome's locket.

Miroku's Wind Tunnel returns when Naraku reveals himself again. The curse was tied to Naraku's existence, so when Naraku resurfaces to execute his plan to absorb Kaguya, the Wind Tunnel also resurfaces. Miroku then uses it to defeat Kaguya's threat, finally putting his family's curse to use for a noble purpose.

Kagura's true desire is freedom. As one of Naraku's incarnations, she is bound to his will and lacks autonomy. When Kaguya promises to grant her heart's desire in exchange for helping her, Kagura agrees because freedom is what she wants most. However, Kaguya ultimately betrays her by teleporting her away when she becomes suspicious.

Mushin entrusts Miroku with passing down the clan duty to destroy a yōkai who threatens to plunge the world into eternal night. This refers to Kaguya, whose plan involves freezing time permanently. The mission marks a new chapter for Miroku's family and their responsibility to protect the world from this celestial threat.

After Naraku is defeated in the initial battle, the spell controlling Kohaku is broken, restoring his human form and freeing him from being Naraku's puppet. Sango finds him waiting in her village, amnesiac but human. However, Naraku later hides inside Kohaku's back, using him as a hiding place to execute his true plan.