The Nichirin blade changes color based on the wielder's innate ability. What element does Giyu Tomioka's blue blade primarily represent?

Total Concentration Breathing involves maximizing oxygen intake. Physiologically, what is the primary effect of increased oxygen on a Demon Slayer's body?

Demons are weakened by sunlight. Which component of sunlight is most directly responsible for this effect?

Muzan Kibutsuji can alter the biology of demons through his blood. What biological process does he likely manipulate to achieve this transformation?

Swordsmiths use rare metal to forge Nichirin Blades. Considering the properties of metal, which of the following properties makes the swords most effective against demons?