Because "hi Kouta Sorry I killed your entire family and a bunch of innocent randos because I latched onto you for being the first person who cared about me and I wanted you to fuck me but you wouldn't fuck me" would only make Kouta hate her and she just wanted to be around him.
In the end Elfen Lied is just the story of a loser cuckquean who couldn't move on.
>>283067649
anime doesnt adapt the full manga and the ending is different, it does have some other changes too
the anime is worth watching before (or after) the manga if you're interested, though really both the anime and the manga are very mediocre and not that good
