hmmm, is that blood I see on her mouth, and wasn't it the case that you make a sister pact by sharing eachothers blood. I wonder, I can't remember if that bloodpact has like any real powers or if it is just mostly symbolic but it seems like Emielle is now in two halfway completed pacts where she has given her blood to Eve, and now she has Yucca's blood.
Wonder how things will develop from here
This is just a theory, but what If Yukka is a yandere, and had planned all this from the beginning, just to get Eve to herself.