After the death of his father, he has the responsibility of his family, and he struggles to fulfill the needs of his family.
Other demons are killed by these flames, but normal humans are unharmed.
Unlike Tanjiro, who serves as the older brother figure, Zenitsu is an easily-scared crybaby who can't seem to keep it together.
My argument is that during her transformations, there are almost no panels where the focus is a certain angle to accentuate sexualized shots or positioning.
He doesn't hesitate to attack anyone he deems a challenge, or that angers him, even if it may seem dangerous or even stupid.
However, the later episodes of this story display that Nezuko develops an ability to face the sun without having any burn.