AN: This is set in the manga post volume 5. Major spoilers.
The emotion was not one that Hans was familiar with and did not know why he felt it. Hans had survived so much in his lifetime and not had anyone or anything affected him in this manner. Why do you make me feel this way, Angel? They were not friends nor were they lovers. Hans had never felt this sentiment for anyone: Not his enemies, friends, or even the girls he had courted as a youth... Yet today, looking at the pain in his eyes, the injuries to his beautiful face, and his blood stained clothes – the emotion consumed him. Regret.
Watching what they did to him when Angel had first arrived had been painful for Hans. Even though years ago they had been enemies, Hans had always liked theyouth who now was an old man. When they fought, they fought fair – each of them enjoyed the challenge of a worthy adversary. The old butler had fought Doc and his assistants ferociously as they chained him to the bare metal table. It was in that instant that their eyes first met. In the moments that followed Hans tried to comfort him with his eyes.
He wanted to do so much more…
Hans ached to hold him in his arms and let him know that the pain would subside.
To feed him his blood so the terrible hunger would be satiated.
And to do so many things to his body to make him forget the pain, the emptiness, and the sorrow.
He was sorry that the Major and Doc would not allow it. They wanted the butler to suffer the worst possible pain through his transformation. Hans wanted to save his former adversary from all of the hurt and every sensation of pain. To a reason unknown to him, Captain Hans was bothered by the injustice of it all. He almost laughed at himself. He who watched Hitler kill millions without blinking his eyes thought it was unjust that one of their enemies suffered pain? Somehow, forcing the Hellsing agent to become a monster seemed incredibly wrong. But since when have you care what was wrong or right? Still all of the others that had been experimented on by Doc had volunteered. The pain may have been just as real forthem but they had asked for it. The butler had not.
It was painful for the Captain to watch the man's spirit crushed, destroyed. Walter, the Angel of Death, had been so strong, powerful, and determined. His beliefs, his loyalty were steadfast and true. His resolve did not waiver with offers of money and power from the Major back then. All of that was different now. With black magic and science they were taking away that part of him, Hans had admired the most – his stubborn, arrogant determination. Now Walter Dolneaz was nothing more then the Major's puppet, slave, pawn, in his master plan to destroy Hellsing. The Captain laughed at the irony. Now, Walter, the Angel of Death was just like him.
The Captain finally overheard from other soldiers that the transformation was complete. When he saw the Angel walking in the corridor, his face was haunted and yet blank. Hans could see the memories of the torture he had endured. Angel did not speak but the Captain saw recognition in his eyes. Hans could not help but grin ever so slightly at Angel.
Hans knew of only one way to get rid of the emotion that was torturing him. He had to bring some comfort to Angel. Someone had done the same for him when he was turned. If Hans failed to, he knew his mind would continue to be tortured by the Angel's pain. The Captain went into Walter's room that day and climbed into his bed. As he filled Walter's body with pleasure, Hans could feel regret slowly slipping away from his soul. And from the smile on his partner's face – the pain was being erased from that of his Angel's.