Slash's first memory is waking up his creator's laboratory, just moments before it was invaded by a horde of angry villagers - unhappy with the supposedly dark arts he was utilising. As he sat up, the mob advanced on the man and cut him down. Slash didn't know much, but he did realise that the man who had given him life had just been murdered.
At this horrific sight, something changed within Slash. A great rage swelled up within him, strengthening his limbs and quickening his actions. He grabbed the nearest weapon - a ceremonial claymore belonging to his creator - and leapt on the unsuspecting villagers. Their pitchforks and torches were no match his great clay bulk and massive blade, and soon he was the only one left standing in the room. It was only once the villagers were dead that the red haze lifted and he realised what he had done.
Knowing that, if caught, he would meet a similar fate, he gathered the clothing from the fallen bodies and disguised his inhuman features as best he could before fleeing from the town. Since then, Slash has carved out a career for himself as a sword-for-hire, never staying in one place long enough to attract attention, and certainly never returning to the town of birth.