Anastazia Zelenska

She is a Rank-2 Hunter who leads a Guild called the Black Dragon Guild.
Black Witch is a hunter who came to the 1st floor of The Tower, Babylon City, by climbing the Tower in Ukraine. Additionally, she is one of the few First Generation Hunters. Before she entered the tower, a war in Ukraine took away the lives of her family. Thus, she became an orphan suffering from her past. Personally, she considers the tower as her hometown. After all, their nationality doesn't matter inside the tower, unlike the outside world.

(Source: SSS-Class Suicide Hunter Wiki)