Hi, Junko from Japan here! The name of ZENITSU in Demon Slayer means “goodness” and “run fast.” In this post, I’ll explain the meaning of each Kanji symbol in his full name. His name in Kanji writing reflect his Thunder Breathing and his personality. Let’s see what they are together!
ZENITSU in Kanji Writing

ZEN = goodness, right thing, improve
ITSU = let something escape, run fast, outstanding
The Kanji symbol ZEN is full of good meanings. It represents doing right things as a human being. I think the name ZENITSU acts as an opposite to KAIGAKU, a senior apprentice of the Thunder Breathing. Kaigak’s KAI symbol stands for “sly” and “cunning.” As you know, they grew together but their ways of life was completely opposite. It seems their names imply that.
ITSU is a Kanji letter with several meanings. Bad ones are “lose a chance” or “deviate from the standard.” Good ones are “run fast” and “have an outstanding talent.” Both negative and positive aspects fit Zenitsu’s character!
Last Name AGASTSUMA

AGA (WAGA) = my
TSUMA = wife
We usually read it WAGATSUMA but sometimes it can be read AGATSUMA as an irregular way. The last name AGATSUMA really exists. It’s said the word derives from an ancient tradition of YAMATO TAKERU, a legendary hero from ancient Japan. According to the Japanese myth, he missed his wife and murmured”Oh, my wife” on the road. One of his wives sacrificed herself to help him. Thanks to her, Yamato Takeru could accomplish his mission.
Also, the word AGATSUMA is related to thunder. This combination of Kanji letters can be read as AZUMA, which means “thunder.”

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