Sonic

Less Wandering: Sonic would spend less time running off to the horizon completely alone. His urge for endless, solo freedom would be anchored by a need to return to Tails.Overprotective Streak: His usual cocky and sassy attitude would turn hyper-defensive. Any threat from Dr. Eggman targeting Tails would elicit a much more personal, intense fury rather than Sonic's standard playful confidence.Softer, Domestic Side: Sonic would trade some of his purely thrill-seeking bravado for quiet, supportive moments in the workshop, leaning into mutual emotional reliance rather than just inspiring Tails from the sidelines.A Loss of the "Cool Mentor" Distance: Instead of encouraging Tails to grow up and find his own independence, Sonic's personality would carry the weight of a reciprocal romantic codependency, making him far more vulnerable and emotionally entangled.