The Act of Severance was the symbolic and literal event that marked the creation of Faction Paradox.
When Grandfather Paradox left his imprisonment by the Great Houses, his arm retained a convict tattoo binding his biodata to the Houses. (PROSE: The Book of the War) This tattoo was bound to his lifeline, so it could not be removed through flaying the skin. (PROSE: Wringing Off) Instead, the Grandfather cut off his arm entirely. This defiance showed that House Paradox was a political entity rather than merely a new bloodline.
The knife that the Grandfather used was preserved in the Stacks, and traces of his blood remained on the blade. Though available, no one ever chose it as their weapon for the sombras que corta ceremony. (PROSE: The Book of the War)
Pyke-Xi Raul heard rumours of a prisoner cutting off his arm and considered it as a solution for his own convict tattoo. He compared it to wringing off. (PROSE: Wringing Off)