While Cha Hae-in has been present in the Solo Leveling anime since the first episode, fans only saw her in action for the first time in the latest episode. As suggested by the anime multiple times, she was stronger than "The Ultimate Weapon" Choi Jong-in, but fans had no idea what depicted her to be so strong.
Fortunately, the anime's latest episode gave fans a glimpse of Cha Hae-in's fighting abilities with her match up against the Japanese S-Rank Hunter, Kanae Tawata. During the fight, Kanae could be seen addressing Cha Hae-in's nickname, "The Dancer." But why is the Korean S-Rank Hunter called "The Dancer?"
Disclaimer: This article may contain spoilers from the Solo Leveling manhwa.
Why is Cha Hae-in called "The Dancer" in Solo Leveling?

As seen in the anime, Kanae Tawata was matched up against Cha Hae-in during the S-Rank Hunters' friendly battle royale sparring match. Amidst this, Cha Hae-in dominated the fight against her, forcing her to think how the Korean S-Rank Hunter's nickname "The Dancer" was well deserved.
"Can't read her movements. The Dancer Cha Hae-in. After seeing her dance-like footwork, it's clear her title is well-deserved." - Kanae Tawata
However, the anime never explained properly why Cha Hae-in was called "The Dancer." This happened due to an alteration made by A-1 Pictures for the anime when adapting from the manhwa.

If one were to check the manhwa, it is very clear that Kanae Tawata not only addresses the nickname but also thinks about how it came to be. As per Kanae, Cha Hae-In was given the nickname "The Dancer" due to the way she would swiftly kill one beast after the other, as if she were dancing.
Cha Hae-in's nickname was effectively attributed to her fluid and graceful fighting style movements that not only made her difficult to read but also made her look like a dancer. She was given the nickname by her teammates from the Hunters Guild after they observed her swift sword movements to slaughter one monster after the other.
Does Cha Hae-in like her nickname?

As revealed by the Solo Leveling manhwa, while people know about her nickname "The Dancer" and address her as such, Cha Hae-in herself never liked the nickname. In fact, she found the nickname so embarrassing that she banned her guild members from calling her that. This is also why not many people call her by that nickname.
That said, the nickname itself is pretty popular, as Sung Jinwoo knew it and used it to address her when he first saw her during his first day as a miner for the Hunters Guild. It is to be noted that, as per the manhwa, even an outsider like Kanae Tawata knew that Cha Hae-in found the nickname to be embarrassing and banned it. The question is, why is this information public knowledge?
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