According to Torras, the story behind that sword was nothing too special. It all started when Torras' ship, The Feral, was sailing across Devil's Water. One day, before reaching Gearwheel Grave, the first officer of the ship gathered some people and started a riot.
The reason for the betrayal was quite simple. Since Torras was hoping to become a wizard at Fey Continent, he took all the treasures and valuables he collected through his years with him. However, a part of the crew including the first officer would like to take their treasures back to their homes and enjoy the rest of their lives rather than taking a risky venture to somewhere unknown.
A fight broke up, which ended with Torras emerging victorious.
Torras cornered and killed his first officer at the rear of the ship. Then he took the officer's sword, stabbed it into the steering wheel, and claimed that he'd spare anyone who came back to him while killing those who would resist.