Gokukoku no Brynhildr is a discount version of Elfen Lied.

The idea is that a regular young man beocomes the only protector and caregiver of a group of girls. Each of the girls possesses supernatural abilities and is haunted by the past.

It is similar to so-called "harem" animes. However, the tone is vastly different, and very much tragic. The plot is gruesome and cruel.