Luciola never smiled, even when they were both very young. No matter how much Dio joked and laughed in a vain attempt to make even a spark of joy show on the older boy's impassive face, he only stared at him and nodded.

Years passed, and they grew older and stronger. Their combat training started under Eumachos, who had once trained Dio's father in the ways of spear and sword just as he now trained the son. It was during one of their many training sessions, when Luciola was fourteen and Dio twelve, that Dio finally saw Luciola smile.

Although they usually sparred with each other—nobody else was skilled enough to put up a real fight against them except Cicada—their tutor had brought a condemned criminal in for Luciola to dispatch that day. Dio knew it was on Delphine's orders; she wanted to make sure her brother's bodyguard could kill, and that her brother witnessed it calmly. When it was over, Luciola's hands were covered in blood (not his, never his), and Dio watched wide-eyed from the sidelines as the corners of Luciola's mouth twisted into a triumphant grin.

Dio stopped trying to make him smile after that.