(Average+) Syraph of the End

Series in one song lyric:
Hey, I just met you
and this is crazy
but here's my full name
now you're my family

Series in more sentences:
A group of orphans witness the death of all adults in the world and are captured by vampires as to become their food dispensers. When they plan to escape years later, it goes wrong and only the short-fused Yu manages to reach the other side of the fence, where he's awaited by a human team of demon hunters.

Yu grows up impatient and eager to avenge his lost friends as a demon hunter, even after learning the disturbing practises he's been made a part of.

It almost looks like this is where The Promised Neverland got their main plot (and horrible ending) from.

A good concept sits in this overstuffed, emotionally rushed story. There was no need to introduce a lethal illness that killed the majority of the human population, later claimed to be the results of global experimentation, to then add vampires who keep human children as "cattle", people transforming into doomsday angels, random beasts roaming the land, and demon-infused weaponry and mental possession.

And there's not only an abundance of story elements, but also characters, none of who get the screen time needed for us to care when something bad happens to them.

This anime is dependant on the relationships people share with each other, but most of it wasn't believable and it didn't help that the majority of characters were a bore. The main character especially. He has no defining traits, except that he's a short-fused boy who's way to eager to call acquaintances "family".
The anime doesn't bother to show him actually interact with his new friends in any meaningful way. It's like the script wasn't written for this many characters, there's only a decent focus on a few of them.

For example, the brown-haired wussy boy and the blonde-pigtailed girl are sidelined very early in the story, and suddenly, it's decided that the first girl character is the one who's in love with Yu. Her personality was really inconsistent and it didn't even matter in the end. None of the romantic storylines went anywhere.

Nevertheless, and perhaps surprisingly after reading my review, I liked it. I would've given it a good rating if it wasn't for the horrible ending.
Season 2 suggests there'll be a season 3, but since this show dates back to 2015, it's safe to say it won't come. This is an incomplete series, be aware when you decide to watch it.