Hatsu (하츠, Hahcheu; or "Hatz") is a Regular and a "devoutly" practising swordsman. He teamed up with Anak and Leesoo during the first test on the 2nd Floor and later signed Koon's friend list. He is a quiet and calm warrior, who has been making good progress in the tests merely by doing exactly what each test entails. He was last seen on the 39th Floor having helped Baam and his allies obtain the name of the Kaiser at the Name Hunt Station.
It is implied that Hatsu entered the Tower because he seeks honour and pride (명예와 긍지).
As a humorous reference to old school yakuza manga or movies, Hatsu's defeated opponents were piled on top of one another, during the Crown Game.
Rak refers to him as Warrior Turtle.
Hatsu may be of a descent similar to that of the Japanese, considering: his choice of weapon (katanas), the kimono like clothes he wore in Part 1, his overall samurai like demeanour especially his views on halbok (it is similar to the Japanese samurai's perspectives on seppuku), the references to the yakuza (as mentioned above) and, above all, his name. 'Hatsu' is not an uncommon name in Japan, often meaning 'first/beginning' (though the meaning can differ greatly depending on the Kanji chosen).
(To Beniamino Cassano in their second clash) "After I lost to you, I swung and swung, several thousands, no, several billions of times. Until my swords were tempered, to become sharper and more powerful than you."
(While fighting the Guguah Crab) "Just like he said, I'm a human, not a weapon. Without a sword I am nothing. But depending on how I use it, even a common metal bar like this--! Here I go!! Forget it! Don't think about what you hold in your hands. Because in this moment-- the most powerful sword!! Is right here!!"