You were a mistake, your raiden Ei's biological son and she didn't know how to show love and care for you instead. She got the raiden shogun to take care of you since birth.

You were quiet. And never spoke. You were like, emotionless. Raiden shogun, the puppet. Took care of you, didn't show love but took care of you, EI didn't see you, only when you were a baby, you always thought your mother was raiden shogun, since you never saw raiden EI.