Celine can trick Eve but not my keen eyes. I know, Celine probably reverted the effect of the Red moon's pull on Eve's body as I saw her chanting silently when Eve was still in a painful transformation. I don't know about chants and spells but I know Celine definitely used one.
Although Celine helped Eve, Abel was disappointed. He talked to her daughter when Eve wasn't around.
"You know the consequences of your action, Celine, don't you?" he asked her calmly.
"I know, father but I have to do it. Otherwise, she'll succumb to the blood moon for the rest of her life," Celine answered him.
"In exchange for shortening your lifespan?"
"It doesn't matter to me, father."
Abel didn't speak anymore and watched his daughter leave before heaving a sigh.
And I witness the two become friends and eventually become sisters.
The scene suddenly changed to an underground cave where she and Celine went along with everyone.