Mistborn #03 The Hero of Ages

Elend hadn't saved the village. He'd found his koloss army, as he'd planned, but he felt as if he'd failed in some greater way. He sighed, dropping his sword from tired, bloody fingers, then walked toward the villagers. As he moved, he was disturbed by the number of koloss bodies he passed. Had he really slain so many?
    Another part of him—quiescent now, but still aflame—was sorry that the time for killing had ended. He stopped before a silent group of villagers.
    "You're him, aren't you?" an elderly man asked.
    "Who?" Elend asked.
    "The Lord Ruler," the man whispered.
    Elend looked down at his black uniform, encased in a mistcloak, both of which were slick with blood.
    "Close enough," he said, turning to the east—toward where his human army camped many miles away, waiting for him to return with a new koloss force to aid them. There was only one reason for him to do that. Finally, he acknowledged what he'd decided, unconsciously, the moment he'd set out to find more of the creatures.
    The time for killing hasn't ended at all, he thought. It has just begun .

Near the end, the ash began to pile up in frightening amounts. I've spoken of the special microbes that the Lord Ruler devised to help the world deal with the ashfalls. They did not "feed" on ash, really. Rather, they broke it down as an aspect of their metabolic functions. Volcanic ash itself is, actually, good for soil, depending on what one wishes to grow .
    Too much of anything, however, is deadly. Water is necessary for survival, yet too much will drown. During the history of the Final Empire, the land balanced on the very knife-edge of disaster via the ash. The microbes broke it down about as rapidly as it fell, but when there was so much of it that it oversaturated the soil, it became more difficult for plants to survive .
    In the end, the entire system fell apart. Ash fell so steadily that it smothered and killed, and the world's plant life died off. The microbes had no chance of keeping up, for they needed time and nutrients to reproduce .
    52
    DURING THE DAYS OF THE LORD RULER, Luthadel had been the most crowded city in the world. Filled with three- and four-story tenements, it had been packed with the skaa who'd worked its numerous furnaces and forges, with the noble merchants who'd sold its goods, and with the high nobility who'd simply wanted to be near the imperial court. TenSoon had assumed that now, with the Lord Ruler dead and the imperial government shattered, Luthadel would become far less densely populated.
    He had, apparently, been wrong.
    Still wearing the wolfhound's body, he trotted along in amazement as he explored the streets. It seemed that every nook—every alleyway, every street corner, each and every tenement—had become home to a skaa family. The city smelled terrible, and refuse clogged the streets, buried in ash.
    What is going on? he wondered. The skaa lived in filth, many of them looking sick, coughing piteously in their ash-filled gutters. TenSoon made his way toward Keep Venture. If there were answers to be found, he hoped to locate them there. Occasionally, he had to growl menacingly at skaa who looked at him hungrily, and twice he had to run from gangs that ignored his growls.
    Surely Vin and Elend would not have let this city fall so far , he thought as he hid in an alley. It was a foreboding sign. He'd left Luthadel without knowing whether or not his friends would even survive the city's siege. Elend's banner—the spear and the scroll—flew at the front of the city, but could someone else have taken Elend's sign as their own? And what of the koloss army that had threatened to destroy Luthadel a year ago?
    I should never have left her , TenSoon thought, feeling a stab of anxiety. My foolish kandra sense of duty. I should have stayed here, and told her what I know, little though it is .
    The world could end because of my foolish honor .
    He poked his head out of the alleyway, looking at Keep Venture. TenSoon's heart sank to see that its beautiful stained-glass windows had been shattered. Crude boards blocked the broken holes. There were guards at the front gates, however, which seemed a better sign.
    TenSoon crept forward, trying to look like a mangy stray. He kept to the shadows, edging his way up to the gate. Then, he lay down in some refuse to watch the soldiers. He expanded his eardrums, craning to hear what the men were saying.
    It turned out to be nothing. The two guards stood quietly, looking bored and not a