Emilia Yandere finally appeared in Chapter 31 of the manga adaptation of the fourth arc of Re:Zero. See below for a comparison of the anime scene with the manga.
Emilia is like this after suffering a lot emotionally from the Echidna trial and also from being alone without Puck and Subaru supporting her.
Fans nicknamed her Emilia Yandere because of her resemblance to Yandere characters.
For those who are curious to see what Emilia yandere is like in the light novel, check out the art from volume 12 below:
What did you think of the manga art? I actually found the manga drawings cooler than the anime ones.
ReZero’s light novel and manga are officially published and is disponible in Amazon.