His sheer innocence and determination for Alois' happiness made her realize that he is different from other humans. Hannah decided to fulfill his wish to kill the townspeople, and he thanked her before dying, something no other human had ever done. This caused her to be attached to Luka, and she was mournful when devouring his soul.Hannah retains Luka's soul inside her, and she soon watches over Alois by becoming his maid. Apparently, she has adopted Luka's desire for his brother's happiness and works to accomplish that as well