Hey I am trying to finde an Ereri fanfiction it has gone missing along with some others (all at ons) I found most of them. I'll try to explain the Story for as good as I can remember.
It starts of with Levi on a yacht(at night) with Furlan, Isabel and Hanji, describing how his uncle Kenny has hunted mer people/sirens(for Experiments) and that he doesn't want to meet one. But then Eren apears singing Once apon a dream (from Maleficent) and I think Furlan or Isabel finds Eren, ¿and gets draged into the ocean? They ascape and Levi is very confused.
Eren has different forms he can change into (pretty mer, scarry siren and able to walk on Land -humans don't know about this one-) Eren is orderd by his father to seduce ans kill Levi because the have been long term enemies with the Ackermanns. He brings Mikasa and Armin on this big Mission. And Grisha helps Eren to get a job at the Ackermann Aquarium. After He gets the job Levi shows him were He will be working. Eren works with the Otters. They talk during a break about two seals Levi healed and later Eren finds the same two seals and shows them to Levi. But Levi doesn't know it's them. Eren is trying to rush the Mission and Grisha says don't rush to Mission. Eren does not listen and things get steamy in the breakroom. Levi figurs out that Eren is a siren and locks him in there. While He thinks what He is going to do Eren escapes to the ocean and hides from everything. Levi finds an empty room and goes home ¿confused/sad?