Mistborn #03 The Hero of Ages

Somehow, he always sensed her. The cavern fell silent. Neither sound nor light bounced off its walls. Vin crouched, the fingers of one hand resting lightly on the cool stone before her. She could feel the thumping, his Allomantic power washing across her in waves. She focused on it, trying to differentiate the metals that had produced it. Yet, the pulses felt opaque. Muddled.
    There's something familiar about them, she realized. When I first sensed this impostor, I thought . . . I thought he was the mist spirit.
    There was a reason the pulses felt familiar. Without the light to distract her, making her connect the figure with Reen, she could see what she'd been missing.
    Her heart began to beat quickly, and for the first time this evening—imprisonment included—she began to feel afraid. The pulses felt just like the ones she'd felt a year ago. The pulses that had led her to the Well of Ascension.
    "Why have you come here?" she whispered to the blackness.
    Laughter. It rang in the empty cavern, loud, free. The thumpings approached, though no footsteps marked the thing's movement. The pulses suddenly grew enormous and overpowering. They washed across Vin, unbounded by the cavern's echoes, an unreal sound that passed through things both living and dead. She stepped backward in the darkness, and nearly tripped over the shelves she'd knocked down.
    I should have known you wouldn't be fooled, a kindly voice said in her head. The thing's voice. She'd heard it only once before, a year ago, when she'd released it from its imprisonment in the Well of Ascension.
    "What do you want?" she whispered.
    You know what I want. You've always known.
    And she did. She had sensed it in the moment when she had touched the thing. Ruin, she called it. It had very simple desires. To see the world come to its end.
    "I will stop you," she said. Yet, it was hard to not feel foolish speaking the words to a force she did not understand, a thing that existed beyond men and beyond worlds.
    It laughed again, though this time the sound was only inside her head. She could still feel Ruin pulsing—though not from any one specific place. It surrounded her. She forced herself to stand up straight.
    Ah, Vin, Ruin said, its voice almost fatherly in tone. You act as if I were your enemy.
    "You are my enemy. You seek to end the things I love."
    And is an ending always bad? it asked. Must not all things, even worlds, someday end?
    "There is no need to hasten that end," Vin said. "No reason to force it."
    All things are subject to their own nature, Vin, Ruin said, seeming to flow around her. She could feel its touch upon her—wet and delicate, like mist. You cannot blame me for being what I am. Without me, nothing would end. Nothing could end. And therefore, nothing could grow. I am life. Would you fight life itself?
    Vin fell silent.
    Do not mourn because the day of this world's end has arrived, Ruin said. That end was ordained the very day of the world's conception. There is a beauty in death—the beauty of finality, the beauty of completion.
    For nothing is truly complete until the day it is finally destroyed.
    "Enough," Vin snapped, feeling alone and smothered in the chill darkness. "Stop taunting me. Why have you come here?"
    Come here? it asked. Why do you ask that?
    "What is your purpose in appearing now?" Vin said. "Have you simply come to gloat over my imprisonment?"
    I have not "just appeared," Vin, Ruin said. Why, I have never left. I've always been with you. A part of you.
    "Nonsense," Vin said. "You only just revealed yourself."
    I revealed myself to your eyes, yes, Ruin said. But, I see that you do not understand. I've always been with you, even when you could not see me.
    It paused, and there was silence, both outside and inside of her head.
    When you're alone, no one can betray you, a voice whispered in the back of her mind. Reen's voice. The voice she heard sometimes, almost real, like a conscience. She'd taken it for granted that the voice was just part of her psyche—a leftover from Reen's teachings. An instinct.
    Anyone will betray you, Vin, the voice said, repeating a bit of advice it commonly gave. As it spoke, it slowly slid from Reen's voice into that of Ruin. Anyone.
    I've always been with you. You've heard me in your mind since your first years of life.

Ruin's escape deserves some explanation. This is a thing that even I had a problem understanding.
    Ruin could not have used the power at the Well of Ascension. It was of