What field does Kathy belong to?

Cassie, an elf in the game Sail, looks exactly like the Muse, but her whole body is purple. She is a dark version of the Muse and evolved into Moyan 'Kezi. Unlike the first four members of the Dark Alliance, Kathy was not created by Sorensen, but by the demon king Smoyati according to the shape of the muse, belonging to the magic domain. Sail is a turn-based tactical web game developed and operated by Shanghai Taomi Network Technology Co., Ltd., which was released in Chinese mainland on June 12, 2009. Its sequel is The Legend of Yue Se (Sail 2). The theme of this work is exploration and the cultivation of elves, and it tells the tortuous and bizarre story of sellers and various elves looking for energy for mankind.