哀願する魔法少女～信じてください！～（Aigan Suru Mahou Shoujo ~Shinjite Kudasai!~）

Yet I did believe her!

Half the human population is in grave danger because of one magical girl.
An evil organization uses an inescapable weapon of mass slaughter, the Magical Nanomaterial Weapon (MNW).

It was magical girl Rina, a symbol of justice, who committed the greatest treason against mankind in all history. Because the girl had leaked the secret data to the evil organization, the dire massacre weapon was created! There is only one week until the enemies fully complete it! To prevent the use of the weapon, the protagonist must find the location of the enemy base from the traitor, magical girl Rina.

But the protagonist, having fallen in love with Rina, couldn't believe that she had turned into a betrayer. He starts an investigation into whether it is true or false. He makes strenuous efforts to clear her name, yet only unfavorable evidences appears, proving the falsification of her records, past ties, and such.

He helplessly interrogates, persuades, and threatens her, yet Rina refuses to talk, only appealing that she does not know anything and wants him to believe her. Impatient top brasses ordered the protagonist to make her confess, even if he needed to resort to shameful acts. He is shaken, because there is no way it would be normal to sexually insult his love, even out of duty.

Nevertheless, he has finally violated her, irritated by her continuing to keep silent. "I know nothing! Do what you want, just forgive me!"—begs she. If he forgives her, she will bear any cruelties, no matter how harsh they will be, and will comply with every one of his demands.

The assault was escalating, and finally the organization's supercomputer was put to use. The protagonist analyzed Rina's body and found her erogenous zones, which he thoroughly stimulated. Covered by murky liquid and gasping for breath, layed Rina. He stared at her and found himself filled with darkish madness, raping her with pleasure.

The protagonist was astonished by the depth of darkness within himself; he was about to be engulfed by it. Yet there is a little time for humanity left. There is no turning back now. People are frightened by MN weapon, so it wouldn't be surprising if they raised several insurrections. More and more chaos was seeping into people's hearts, but the organization of justice was in the same situation.

There is only one way to help them all—to get the enemy base's whereabouts from Rina. No matter how much she begs for mercy, there is only one path left for the protagonist now. But even so, when he looks down at a frightened Rina, he cannot resist his desire.

"Is that really the right deed?"

[Translated from DLsite]