the anime is about a boy, he had a normal life.
some when a girl appeard, from another world and
they started to fight other monsters to be able to return
the girl to where she belonged to.
her goal was to go back to there from where she came
and the boy was trying to help her.
i remember that they also fought some people with those
'' monster's '' which whom they had a contract.
at episode 10 or something around that courner
2-3 of the contractors fought a very strong opponent
but they had no chance of winning, thats why one of them
had to sacrifice his life. ( i remember it was a monster with a gun )
and that the attack was a special shot, if he used it he would die.
but it was also useless, so the main character
the contractor and the girl which came from the '' other world ''
had to deal with the strong monster.
i really wanna watch it again, but i forgot its name..
right answer -> 100 fg