Despite the Demon Slayer anime's title sharing the name of his very profession, Zenitsu Agatsuma is petrified by demons. Prone to extremely long-winded fits of hysterical screaming, some fans find the Thunder-Breathing swordsman to be over the top and annoying. However, his outright terror in the face of disfigured, evil monsters is much more relatable than Tanjiro's ability to feel sympathy for them.
In a world full of inhuman creatures and abilities, Zenitsu is easily the most human character in Demon Slayer. The young man is a surrogate for many anime fans who experience crippling self-doubt in the face of adversity. Even as a character with low self-esteem and deep-rooted self-loathing over what he perceives as his own cowardice, Zenitsu never gives up -- despite how often he screams that he wants to.
Behind all of Zenitsu's eccentric behavior is a genuine desire to do the right thing. He took a savage beating from Inosuke to protect Nezuko, despite knowing she is a demon. Zenitsu had only just met Tanjiro, yet he was willing to lay down his life to guard someone who was precious to his new companion. And this was before ever seeing or meeting Nezuko.
Most shonen protagonists are so obsessed with their goals that it consumes much of their personality. Granted, Zenitsu is not the lead protagonist, but he still displays personal desires that are not demon-related. Though his approach with women needs to be toned down, it is still indicative of a desire for an actual life. Constantly being rejected by these women is certainly more relatable than any Breathing Technique he could learn.
For all of his flaws and fears, Zenitsu is quite the capable warrior in Demon Slayer -- as long as he's unconscious. His Thunder-Breathing technique, Thunderclap and Flash, has been used to devastating effect against several demons. At first glance, the fact that he can only perform this technique while asleep comes off as gimmicky and little more than comic relief. However, this is exactly what makes him the bridge between the audience and the show. Zenitsu wants nothing more than to be a strong and dependable warrior and hero, and just like in the real world, it only happens in his dreams.
Though Zenitsu exhibits the most cartoonish behavior in Demon Slayer, it is ironic because he is the most human. Facing off against demons with reality-altering powers armed only with a sword and super lungs is a daunting task. Anime viewers are so acclimated to supernatural worlds and beings that the reality of the situation tends to get lost. Zenitsu bucks the trend of the courageous and poised hero who doesn't flinch in the face of danger; instead, reacting like a normal person would -- by being so scared that he loses consciousness.
At the end of the day, Zenitsu's greatest obstacle to overcome is himself. Mind over matter is easier said than done, and like many people, it is a daily struggle for the young demon slayer. To anyone whose self-doubt holds them back, Zenitsu is a symbol of perseverance. In the words of his teacher, "It's all right to cry. It's all right to run away. But don't ever give up."