My ASO is My One and Only

The world stands on the verge of a full-scale invasion from the Demon Realm and Carlo finds himself driven to the edge when the Demons pull out the perfect trump card for the final push. The Church makes the first move, though, and dispatches one of its best Paladins to save not only Carlo's life but also his soul. Can he save himself, Maya and everyone else he cares about or is his desire foolish greed that will cause him to lose everything?