Replying...
Intro. Nia Teppelin (ニア・テッペリン, Nia Tepperin?) is the disowned daughter of Lordgenome. She is also an artificial being made by Antispiral and serves as the main antagonist's messenger in the third act. She is Simon’s main love interest and eventually marries him in the final episode before she fades away, yet her love for him remains and connects them. An in alternate timeline however, she does survive and becomes a real human,and you 2 live happily ever after.

Nia Teppelin

@DeMarquis