WARNING: The following contains spoilers for Demon Slayer: Kimetsu no Yaiba #205 by Koyoharu Gotouge, John Werry and John Hunt, now available in English from Viz Media.
Demon Slayer's Tanjiro Kamado continues to use out every skill in his arsenal while taking on Muzan Kibutsuji and his demonic forces. During a fight against Akaza -- the Upper Rank 3 Demon -- Tanjiro uses the Transparent World technique his father showed him at a young age. With the recent release of Demon Slayer Vol. 18, let's take a look at Tanjiro's Transparent World, which features heavily throughout the volume.
The Demon Slayer's swords and various breathing techniques -- like Sun, Water and Wind -- are their primary tools for combating Demons. Later in the series, Tanjiro and the Hashira gain the ability to unlock their Demon Slayer Marks that grant a dramatic increase in power, speed and senses. As Tanjiro and Giyu Tomioka, the Water Hashira, battle Akaza, Tanjiro's mind races to find a way to combat the Demon's frustrating ability to track fighting spirits.
Tanjiro Remembers His Father's Lesson
With his Compass Needle power, Akaza can sense an enemy's fighting spirit, which allows him to detect incoming attacks. While reminding Tanjiro of how Inosuke can feel where someone would attack him based on their malicious intent, he has flashbacks to memories with his father, Tanjuro.
Tanjiro and his father discuss the familial tradition of performing the Hinokami Kagura dance, where an offering is made to the Fire God by dancing from sunrise to sunset. Despite his failing health, Tanjiro's father explain he no longer feels exhaustion while dancing since he's perfected the motions and can reach a domain called the Transparent World. One night shortly before his death, Tanjiro's father takes his son outside, where they encounter a massive bear stalking near their home.
In the face of this bear, Tanjiro's father remains calm even as he swiftly cuts its head off in a flash. Tanjiro notices that his father's scent never changes, and there was no fear or ill will towards the bear. While his father told him never to forget what he saw, it isn't until now that Tanjiro understands that it was a lesson in reaching the Transparent World.
Tanjiro Sees the Transparent World
By reaching a state of unparalleled calm, Tanjiro, like his father, can focus to such a point that he can control blood vessels and muscles as quickly and easily as blinking. The Transparent World domain allows Tanjiro to see the world as if looking through an X-ray where he can analyze breath, blood flow and the movement of muscles and joints. He also strengthens perception, making the world around him appear to move in slow-motion.
With his newfound ability, Tanjiro eliminates a detectable fighting spirit and can battle against Akaza more freely. Tanjiro analyzes Akaza's movements until he finds a perfect moment to strike, using Hinokami Kagura to cut off his head successfully. Though the fight persists with the Demon's headless body continuing to attack, Akaza eventually -- and gratefully -- admits defeat to Tanjiro for beheading him.
Muzan's Encounter With Yoriichi
Other Hashira and Yoriichi Tsugikuni, the creator of the first Breathing Style, can also achieve this ability. It proves an imperative advantage against Muzan both during Yoriichi's encounters with King of Demons and the final clash with him. Much like the technique of Sun Breathing, the Transparent World is kept alive thanks in part to the Kamado family, who continued Yoriiichi's valuable traditions.
