Black Cross... a reincarnation of planet Earth that is 3 times it size after it was destroyed in the armageddon war which is a war declared by God and Lucifer after the war God created Black Cross to give humans a new home and God and Lucifer gave humans company by letting angels and demons to inhabit the world with them and the humans were able to live in peace with them however monsters were not a part of this warm acceptance. To humans monster were bloodthirsty creatures whose only goal was to devour every single thing they see, but little do they know that this was partly true. Monsters like all living beings were created by God but monsters are actually reincarnated humans who were close to being allowed in heaven but a certain sin was holding them back, so instead of sending them to hell God showed mercy by reincarnating them as a monster that represent the sin they carried and with fragments of their memories as human/angels/demons and while yes they are created is to eat humans, angels, and/or demons but they do this to limit the numbers so that they don't overpopulate the planet. The pros of being a monster is that once you die you will be reincarnated again until you pay off your sin which means hell is not an option. The cons is you keep dying and dying and dying and you will still remember how you died and the pain you felt and in worse case you lose some or most of your memory in your past life which can be very haunting. Also your body is the sign on whether you are paying off your sins or you are doing worse sins. The closer you are paying off your sins the more human like you will become; however, you will not be turned back into your past self but instead a beam of light will shine on you and will give you a choice whether to go to heaven now or wait until you die, so either way your sins are paid off and your going to heaven. But if you are causing more sins then you will become an abomination which is the nightmare form of a monster and the thing that all (even monsters) fear because the only thing on your mind will be eating and killing, and once you die while you will be reincarnated again you will be haunted by the souls you have mercilessly killed while you are an abomination until your sins are forgiven. Now we go to the story of the lovely couple Kaila and Blu who are enjoying their nice lives in isolation and peace but after a certain thought comes up from one of them they will embark in a huge vorarephilic adventure that will help not only monsters but everyone else towards world peace.