Gregor was an Ussuran peasant, unremarkable except for his size and athletic ability. By the time he was sixteen, he was not only the champion wrestler of his own village, he could beat the champions of all the neighboring villages. He got in the habit of keeping order at the local drinking hall simply by picking up anyone who got rowdy and holding them immobile until they settled down.
So when the local boyar, Ilya Markov Okhotnik, condescended to make a rare visit, and pawed one of the serving girls, Gregor acted before he thought: and then, when he realized that laying hands on his lord could not end well, he panicked and gripped him even tighter.
There was a loud crack. The entire hall fell silent. Then some of Gregor's friends hurried him away, while others attended to the fallen lord. Gregor hid in the woods until he heard the news: the boyar was crippled and would never walk again.
There was nowhere in Ussura where he could be safe. Gregor fled his homeland, never to return. Eventually, he settled in Altamira, and almost forgot about the past mischance that sent him into exile. But Okhotnik has not forgotten, and has spent years trying to trace Gregor. Recently his inquiries have borne fruit: riverboat traders brought word of a performing wrestler in Altamira, and further inquiries positively identified Gregor. Okhotnik is determined that Gregor suffer for his crime: first by crippling him, and only then dragging him back to Ussura to face harsh justice.
Background: Nemesis 1