"You've met Malfoy before?"
Harry explained about their meeting in Diagon Alley.
"I've heard of his family," said Ron darkly. "They were some of the first to come back to our side after You-Know-Who disappeared. Said they'd been bewitched. My dad doesn't believe it. He says Malfoy's father didn't need an excuse to go over to the Dark Side."
(Harry Potter and the Sorcerer's Stone)
When you say ‘some of’ is the qualifier, does it mean ‘some of’ modifies ‘the first’? Or unlike pre-modifiers, ‘some’ is modified by ‘the first’?