Although the two had a tight bond in Sonic 2006 (perhaps not romantic, but who knows), by the game's end, Blaze's relationship with Silver had all but ceased to exist, the only reminders being mostly relegated to the series' spin-offs and non-canon games. Meanwhile, Sonic was the one who got Blaze to realize that she was not alone in her struggles and to be a more open and sociable person. Sonic also had the honor of being Blaze's partner-in-combat during her struggles to recover the Jeweled Scepter. Sonic is undoubtedly Blaze's closest friend, and though it's unlikely there's anything romantic between the two, Sonic is the closest to her heart.