Human is a koloss that was spiked some time before the Lord Ruler's death, as well as a relatively minor character in the third novel in the first Mistborn trilogy, The Hero of Ages. Human, when pushed, showed Vin how koloss were made, and served Vin to a limited degree during the book.
Origin
Before he was spiked to become a koloss, Human was a skaa rebel known as Vershad. He was the leader of a rebellion in the southeast of the Final Empire, in the same area where Clubs fought in his youth. Vershad lived in the desert outside the borders of the Final Empire, and crossed the border to raid outlying villages and steal supplies. His preferred methods involved converting the local skaa population to his side, and convince them to give him supplies. In return, he and his band would "raid" the village, only attacking the mansions of the nobility. This allowed the skaa to get revenge against the nobility, as well as earning more supplies due to the assumption that their food stores had been raided as well.
Vershad was a charismatic and intelligent skaa, managing even to keep his band alive when the Lord Ruler began to turn his attention to them. Eventually, however, the Lord Ruler sent a koloss army against Vershad and his men, with the aid of an Inquisitor, who set an ambush as well as betraying the rebels. For their crimes, Vershad's men were slaughtered, and he himself was turned into a koloss.
As a koloss, Human retained much of his intelligence and determination, which made him a noticably clever koloss.[1]