My Little Demon Child

Mephisto recused a tortured demon child from the hands of the Vatican and gives Rin a task of taking care of him. Who is this demon? Why did Mephisto saved him? And why was he given to Rin? Would he be killed by Yukio who was irritated that a demon now lives with Rin? Or will he be welcomed into their lives?

I hate summaries! Just read the story I bet you would like it! It's a Blue Exorcist and Assassination Classroom crossover!