After their homeworld was destroyed, the surviving Shri'Traccal returned to Earth. Only a small number of ships that survived the battle against the Xsaindi were able to return to the little blue planet, most of them so badly damaged, their leaders had no choice but to descend to the surface and claim certain parts for their own clans. Europe wasn't one of the favorite places for them to set up new settlements, as the weather was too hot and dry or too cold and wet.
One of the Tároc who did settle there was Tároc Latarji, a tall, domineering and egocentric brute, with his equally brutal clan.
When the Shri'Traccal returned to Earth for the second time, there were still enough human males present in Europe, at least compared to the other continents, for the human race to have a chance at survival.
Within a year of the Kirll clans settling in at various parts of western Europe, there wasn't a man to be seen alive, they had all been hunted and killed.
The females were hunted as well, only for a completely different reason... After all, the human females had identical reproductive organs to that of the Shri'Traccal women, and Latarji started to experiment on them as well as using the woman for their own pleasures.
When the other Tároc discovered this, it became strictly forbidden for them to abuse the human females, much to Latarji's chagrin.
He cut himself off from the rest of the Shri'Traccal and went his own, cruel and domineering way, allowing his men to bring fear and terror among the Europeans females.