I spent long years searching for my Guardian. In my wanderings in the wilderness, I happened across groups of humans fleeing the knives of the Fallen, or dying at their hands.

Although I'm only a ghost, I resolved to help what people I could. In a way, I could stand in for the Guardian I hadn't found. I couldn't fight, but I could still help.

The next group of humans I found were trying to reach the Last City, with its protective walls. I offered to guide them there, although it was hundreds of miles across rough terrain. But I knew the way, and they didn't.

Our journey was a long, cold, hungry one. As the days passed, I struck up a friendship with a young human named Tiercel. He was a thin, gangly youth, determined to take a man's responsibility on his bony shoulders after his father's death at the hands of the Fallen. He worked hard and cared for the others, and even more remarkable, complained little.

At night, when he had guard duty, he would say, "Tell me stories, Ghost. You know such wonderful things."

And I regaled him with stories of the Traveler's struggles against the Darkness, epic battles and costly defeats. Tiercel sighed in bliss.

When I found my Guardian, I hoped I liked them half as much as I liked Tiercel.

He respected me for that, too. "When you find your Guardian," he said wistfully, "I hope I'm still around. I'd like to meet them." Then we'd talk about Guardians and ghosts. He sensed my loneliness during these conversations and felt sorry for me. I couldn't always conceal it-my spark was designed to bond with another's. Without my other half, I was sad and incomplete.

We were less than a hundred miles from the Last City when the Fallen ambushed us.

The Twilight Gap crossing was grueling at the best of times. Everyone was cold and tired, and hadn't much food. The Fallen attacked because we were easy marks. They love the thrill of the slaughter.

The only thing I could do was warn my humans a few minutes before the attack. They weren't wholly caught off guard. But in the end, it didn't matter. The humans I had been shepherding died on the unforgiving spears and knives of the aliens.

Tiercel fought and wounded a Dreg with a stolen knife. But the Dreg stabbed him between the shoulder blades, laughing. Leaving the knife in Tiercel's back, the Dreg moved on to more challenging targets.

"Tiercel!" I called, as my friend crawled away from the battle. "Here! Here!"

A stream flowed in a deeply-cloven bed nearby. Beneath the overhanging bank, I had found a tiny alcove, not quite a cave. I guided Tiercel to it. He crawled inside and wedged himself against the damp stones. We hid there until the Fallen finished their ghastly work and silence fell.

Tiercel pulled the knife from his back with a groan. He let the bloodied weapon slide into the nearby stream.

"It's a good knife," I told him. "You should keep it."

He smiled at me with blood on his lips. "I won't need it in a minute."

The knife had punctured one of his lungs. I wept inside myself. "Tiercel, I'm an awful friend. I couldn't save you-or any of the others."

"Don't worry about me, Ghost," he said, resting his head on the rocks. He coughed up blood that ran down his shirt. "Go find your Guardian. Guardians save people. Like us."

I couldn't bear to watch him die, like so many others I had failed to save. But I couldn't leave him to die alone. So I hung in the air nearby, tracing him with a futile healing beam. He wasn't my Guardian, and I didn't know him inside and out. Not well enough to rebuild him cell by cell. I mended a little of the knife's damage-not enough to save him, but enough to ease the pain.

"Tell me-tell me about the Light," he wheezed, his eyes beginning to glaze. "Maybe it'll be waiting for me ... on the other side."

I told him of the Traveler's wonderful power of life and restoration, the very power that beat within my core. Tiercel listened and smiled. He struggled to draw breath, but he smiled. And eventually, even those weak, struggling breaths came to an end. His smile faded.

I floated there beside the body of my friend. Desolation clamped over me. I hadn't found my Guardian. I had let these people die. My best friend lay dead beside me. I was a failure of a ghost, destined to become one more lifeless shell slowly sinking into the earth with the ages.

"I'm sorry, Tiercel," I whispered, touching his cold face with my shell.

Then I felt his spark.

Stripped of life that concealed it, Tiercel's spark burned bright within him, calling to me, singing to me of warmth and Light and companionship. He was my Guardian. How was he my Guardian? How had I not known? Or perhaps I had sensed it all along, and that was what drew me to him.

"My Guardian, O my Guardian," I whispered. I opened my shell, letting precious Light escape me, and bonded my spark to his. Our souls joined, more powerful now that we were together.

I poured Light into him, mending the damaged lung, the severed blood vessels. Then I called him back to life in a rapturous surge of Light.

Tiercel awoke with a final cough. "Ghost," he said, blinking at me. "I told you, it's all right. Go find your Guardian."

"You are my Guardian," I choked, and flew into his hands.