Not gonna bother mr director but basically Yamato and Rebellion are still Sparda's swords - one to divide, one to unite. Rebellion only became Devil Sword Dante after Dante stabbed himself with Rebellion's hilt, absorbed DSS and melded everything with his demon essence
Yamato is Vergil's sword, but most devil arms seem to come from the soul of a demon after they're beaten. So if that sword is a keepsake from Sparda, it seems strange to be in his possession if it existed before Vergil.
This is something that has been a mystery to me that only a game about Sparda would be able to reveal.