Shingeki no Kyojin, Yakusoku no Neverland Recommendations
My first impression of this anime : 'This feels awfully like Attack on Titan'
There are three main protagonists like Eren, Armin and Mikasa. They were surrounded by wall and trying to escape it (Although the wall doesn't play that big role in here like in Attack on Titan does). There's also these human eater creatures. Also I think Eren say something similar about them being trapped inside a wall like cattle. Well, in this case they are literally the cattle.
I'd say there are also Death Note feel to it, but I lean more towards Attack on Titan.
A group of people trapped inside of walls trying to escape from "monsters " that are trying to eat them. Both groups do some kind of training, trying to fight/escape the titans/demons. The main three characters of each anime have some similarities as well.
Both shows feature characters inside an area closed off by a wall/fence, possibly keeping someone/something out. Without spoiling much, they're both dark and are based on the main characters trying to survive their situations.
Both manga are about humans trying to surrive in a world in which they aren't the dominant predators anymore.