I can see now why you asked the question. But if I'm not mistaken, I did hear that they were handed down to them. Maybe they weren't just given to them, maybe they had to prove themselves first? Kind of like, proving yourself as a demon slayer in order to gain their rightful weapons. Sort of a test from their father. Maybe he wanted to know if they could handle the responsibilities. The message being, don't raise your sword, if you're not strong enough to hold it. And perhaps Vergil reads too much into this, what with the death of his mother beforehand. That's why he takes the test more seriously, and seeks to gain more power. But Dante, apparently being more rebellious, just leaves and doesn't take it seriously. Because Dante's characteristics and persona, are just that he didn't care much when he was growing up. He never knew how to look remorseful and show his feelings. Sometimes he did, but very often. And mostly just to his brother. So maybe that's what makes Vergil fight his brother, because his brother doesn't seem to care to him. It was a big deal that Dante refused to gain the power of their father. Vergil saw it as an opportunity to be like him, to be better. But Dante refused that power, because he thought that too much may go to him and make him change. And in the end Vergil regretted his decisions, when he supposedly failed to defeat Mundus. And I expect if he still is alive, which I'm guessing he is, he'd realise that Dante did care and he was fighting for what he believed in all along. It never meant he didn't care, and Vergil just never realised that.
