What was this all about? All the "demons" had that scar on their back in the same spot. They did it to the kids because I'm assuming they wanted to totally finish converting them to be their pawns.
...Bring On The Zombies...
Messing with their hearts, literally and figuratively?
shareI felt it could be seen as purely symbolic,
as a removal of their social/parental/ethical restraints - part of their initiation.
Or the permeant removal of their Angelic wings, or the chance at ever owning a pair.
If you were religious, the symbol of a person's entrance and acceptance into heaven.
Or possibly the opposite of an exorcism, in order to show that their souls had been removed.
Their source of empathy drained?
That's why the film resonants... it fluid opening to interpretation and sudden closing to definitive answers.