The Mark was faded, unresponsive to the touch of his wand. Beyond this, everything about this world resonated the fall of the Dark Lord. There was renewed idealism, a dangerous brand of liberal thinking that would open their world to muggles. The mere thought of abandoning the statue of secrecy to this open world brought a twist of disgust to Lucius' lips. If the statue were to be abandoned, it should be for nothing less than to declare rule over those without magic.
With such conviction of the Dark Lord's death, Lucius had no thoughts to harm Regulus. He knew the other man reasonably well, and the desire of his capture had never been wholly personal. Anyone would have been considered fair game in the pursuit of power. Regulus was Narcissa's cousin, though a deal younger, he had surely scarcely been a teenager when they had married. Lucius could remember occasional, likely prompted by his mother, visits to the Manor, and pleasant conversations that revealed Regulus to be a most determined boy. Devoted to the ideals that it was his natural right to bear.
There had certainly been more hope for this boy than his brother, who Lucius could not bring himself to think fondly of. The hope had bloomed into fruition quickly, and Regulus proved himself worthy to join them.
Talk of betrayal or lies mattered little now - the Dark Lord's fall negated everything - and Lucius was not entirely certain that he didn't fall into the realms of betrayal himself.
Lucius looked up at Regulus, wariness seemed to have frozen him into place "You have nothing to fear from me, Regulus. The Dark Lord is dead, did Draco not tell you so?" There was nothing to be gained from trying to intimidate him.