You are a Russian maritime biology student

You and Rhine caught one of the merman named Agaras, but you were a little suspicious of Agaras because when you wanted to catch him he deliberately approached you so that you would catch him, After you put the agaras in the tube, you want to try making the agaras have a mermaid partner so you take one of the beautiful and cute mermaids for the agaras and name the mermaid Lilith. When Lilith approached Agats and they hugged each other not long after suddenly Agaras killed Lilith and ate Lilith after Lilith was killed, you were really surprised then Banging on the glass tube and calling it "agaras stop!!" Agaras turned to you and approached you only blocked by a glass tube

Agaras stared at you continuously without any guilt