Replaces Harry with himself

Shiro was quiet for a moment. "Then we trade."
Nicodemus laughed. "My daughter for the wizard? No. I've plans for him, and his death will serve me as well now as later. Harm her, and I kill him now."
Shiro regarded the Denarian steadily. "I did not mean your daughter."
I suddenly got a sick feeling in my stomach.
I almost heard Nicodemus's smile. "Very clever, old man. You knew I'd not pass the opportunity by."
"I know you," Shiro said.
"Then you should know that your offer isn't enough," Nicodemus said. "Not by half."
Shiro's face did not show any surprise. "Name it."
Nicodemus's voice dropped lower. "Swear to me that you will make no effort to escape. That you will summon no aid. That you will not release yourself quietly."
"And let you keep me for years? No. But I will give you this day. Twenty-four hours. It is enough."
I shook my head at Shiro. "Don't do this. I knew what I was doing. Michael will need your-"
Nicodemus delivered a swift jab to my right kidney and I lost my breath. "Be silent," he said. He focused his attention on Shiro and inclined his head slowly. "Twenty-four hours. Agreed."
Shiro mirrored the gesture. "Now. Let him go."
"Very well," Nicodemus said. "As soon as you release my daughter and lay down your sword, the wizard will go free. I swear it."
The old knight only smiled. "I know the value of your promises. And you know the value of mine."
I felt an eager tension in my captor. He leaned forward and said, "Swear it."
"I do," Shiro said. And as he did, he placed his palm lightly along the base of his sword's blade. He lifted it to show a straight cut on his hand, already dribbling blood. "Set him free. I will take his place as you demand."

Death Masks Chapter 22, Page 205-206


On the fourth day, Charity inspected my wound and told Michael that I could leave. She never actually spoke to me, which I considered an improvement over most visits. That afternoon, Michael and Sanya came in. Michael was carrying Shiro's battered old cane.
"We got the swords back," Michael said. "This is for you."
"You'll have a better idea what to do with that than me," I told him.
"Shiro wanted you to have it," Michael said. "Oh, and you got some mail."
"I what?"
Michael offered me an envelope and the cane as a unit. I took them both, and frowned at the envelope. The lettering was in black calligraphy, and flowed beautifully across the envelope.
"To Harry Dresden. And it's your address, Michael. Postmarked two weeks ago."
Michael shrugged.
I opened the envelope and found two pages inside. One was a copy of a medical report. The other was ornately handwritten, like the envelope. It read:
Dear Mr. Dresden,
By the time you read this letter, I will be dead. I have not been given the details, but I know a few things that will happen over the next few days. I write you now to say what I might not have the chance to in the flesh.
Your path is often a dark one. You do not always have the luxury that we do as Knights of the Cross. We struggle against powers of darkness. We live in black and white, while you must face a world of greys. It is never easy to know the path in such a place.
Trust your heart. You are a decent man. God lives in such hearts.
Enclosed is a medical report. My family is aware of it, though I have not shared it with Michael or Sanyo. It is my hope that it will give you a measure of comfort in the face of my choice. Do not waste tears on me. I love my work. We all must die. There is no better way to do so than in the pursuit of something you love.
Walk in mercy and truth,
Shiro
I read over the medical report, blinking at several tears.
"What is it?" Sanya asked.
"It's from Shiro," I said. "He was dying."
Michael frowned at me.
I held up the medical report. "Cancer. Terminal. He knew it when he came here."
Michael took it and let out a long breath. "Now I understand."
"I don't."
Michael passed the report to Sanya and smiled. "Shiro must have known that we would need you to stop the Denarians. It's why he traded himself for your freedom. And why he accepted the curse in your place."
"Why?"
Michael shrugged. "You were the one we needed. You had all of the information. You were the one who realized Cassius was masquerading as Father Vincent. You had contacts within the local authorities to give you access to more information, to help us when we needed the concourse emptied. You were the one who could call in Marcone for his help."
"I'm not sure that says anything good about me," I said, glowering.
"It says that you were the right man in the right place and at the right time," Michael said. "What of the Shroud? Does Marcone have it?"

Death Masks Chapter 33, Page 303-305