help finding a manga

I read a manga a year ago online and can't for the life of me remember the name. all i remember is the premise. it is basically about a kid who got left on earth while everyone got sent to another world to learn mana and magic for the new world update. but because he was forgotten, god sent him an angel to help and protect him. but, because of the main character plot, the angel falls for him. i won't tell the rest so not to spoil it, though i would be grateful if anyone finds it for me.