Zenitsu Agatsuma (Kimetsu no Yaiba) possesses a heightened sense of hearing allowing him to discern layers of overlapping sounds and even hear a person's thoughts and instantly understand their personality from the subtle sounds they produce.
Zenitsu and Tengen Have Perfect Hearing
His extremely sensitive hearing allows him to fight while completely asleep. He can detect danger from the slightest noise and even tell what kind of person someone is just from the sound of their body.
Enhanced Hearing: Zenitsu possesses a heightened sense of hearing, allowing him to detect danger from even the faintest of sounds. With this, he has displayed the ability to decipher layers upon layers of sound in one of the brothels and even in the Infinity Castle.
Zenitsu possesses enhanced hearing, allowing him to detect even the faintest of sounds, such as breathing, a heartbeat or blood circulating. He can hear movements from humans, animals or demons, and if he truly concentrates he is able to read people's thoughts.
Basically, his hearing is really sensitive and so enhanced that everything around him seems to make loud noise, he can even hear other people's heart beat if he focus to them enough.
Demon Slayers are known for their strength and bravery in battle, but not Zenitsu. Despite his cowardice, he's one of the strongest in the series.
Inosuke (Demon Slayer)
Inosuke also has some great one-liners and reactions to moments in the show, and is responsible for some of the funniest quotes in the series.
But, comparing the two characters in their best forms, Zenitsu might be just a tad bit faster owing to his Godspeed move.
His real power shows when he is aware and awake, he was able to outmatch the new upper rank six demon, Kaigaku. At this point Zenitsu has manifested his speed and power, and he was also able to keep up with the Demon King, Muzan, even when weakened.
To sum it up, it is possible for Zenitsu to fight without fainting and it has been shown clearly in the manga. While he only perfected the first form, he trained hard enough to create a new form that didn't exist before.
Superhuman Hearing: Zenitsu has always had enhanced hearing, being able to hear what others can't. He is able to hear a faint difference that is normally indetectable to humans in the sound of a moving human and a moving demon. His hearing gives him extra awareness for danger.
Thunder Breathing is one such technique that Zenitsu has used to great effect in the series. Of course, Zenitsu is only the master of the first form, but it goes without saying that the other techniques of Thunder Breathing will also be awe-inspiring to witness in Demon Slayer.
One such ability is the super-hearing that Uzui and Zenitsu both employ. Paralleling Tanjiro's superhuman sense of smell, Zenitsu's hearing surpasses ranges discernible to humans, allowing him to pick up on details like emotional vibrations.
When facing Kaigaku during the Infinity Castle arc, Zenitsu debuts his brand new exclusive Seventh Form to Thunder Breathing. With this, Zenitsu finally has more than one tool in his arsenal and has overcome his own personal doubts and fears. While Zenitsu's character arc is short, this is a fantastic ending to it.
Zenitsu — Anxiety
Crunchyroll, Inc. To the surprise of absolutely nobody, Zenitsu is anxiety incarnate. He starts out the series so paralyzed by fear that he can't even fight when he's conscious, and so he's only able to fight when he's passed out. It's like sleepwalking, but much cooler.
Zenitsu has some combination of RBD, narcolepsy, sleepwalking, and lucid dreaming that allows him to behave as if he were awake while asleep. Thanks to his extensive training and superhuman hearing, he's able to detect and fight demons in this state.
Tanjiro Is Strong, and Stronger than Zenitsu as he uses Sun Breathing.
Tanjiro's confidence alone would allow him to overpower the other boy, but his knack for strategizing and skill with a sword would certainly help too. Given how talented Tanjiro is, it's likely he'd defeat Zenitsu, even if the latter could fall asleep and call on his powers.
With his master gone, Zenitsu can no longer learn the remaining five forms.
slow ?! , Deku was able to dodge and hit in a split second. And yet he is clearly faster than Zenitsu .
Tengen Uzui
This Breathing Technique gives him echolocation and other advanced hearing abilities. Even though he is large and muscular, and uses that to his advantage, his fighting style relies more on aesthetics and flashiness. He is the fastest Hashira, and the second physically strongest.
The young Tanjiro is not only one of the greatest demon slayers, but thanks to his kind nature, he's also one of the most honorable characters of the series. Tanjiro not only showed selflessness and love towards his sister and the people he cared for but even showed kindness towards his demonic enemies.