>>149155804
It wasn't because he "became enamored with her" it's because the VA they hired gave her a more upbeat and friendly energy and they felt mean Marcy would just be an inferior/redundant Sasha.

>Marcy really changed when the actor Haley Tju was introduced to the equation. Haley brought such a positive, energetic, lovable vibe to this character. I'll be honest, she was originally written a little more cold and calculating... but as we were casting and as we started writing and really getting into the characters, that felt like a little bit of a repeat of Sasha. It felt like, "Well, let's do something different. Let's really create a character who brings something new and exciting and bubbly to the group dynamic."

https://www.cbr.com/amphibia-matt-braly-interview/