Monster - Karma x Nagisa

Alternate universe, setting is in the modern-post apocalyptic world - Vampires and Humans, The humans fight to keep themselves afloat, to rise against this new threat. The nuclear sirens came without warning, a flashing light and a mushroom-like cloud was the last thing many saw. Earth was no longer in the human's grasp, for vampires now fought to take it all, take it all away. No more famines, the humans would submit to be livestock or die. Amidst this chaos two old friends meet, only for one of them to realize that the other now had fangs.

Disclaimer: I do not own Assassination Classroom neither do I own the picture, all of those rights remain to their artists - who I may say are very talented.