Portal

The eath is in danger, or should I say the human race. Demons are filling their land to feed on their heart and soul. The angels are the only race who can stop them before all the humans get their heart ripped out by demons, so every 200 years the angels send out 4 chosen warriors to fight the demons and protect the humans. It sounds easy, but of all the warriors who where sent to earth only 2 survived, one of them returned to heaven but the other turned into a powerful demon. Angel hearts give demons eternal life, so every 200 years millions of demons hunt the angels in hope of eating their heart.