Knuxsu didn't just happen, snap, like that. It all started in Knuckles the Echidna issue #4.
How Knuckles and Julie-Su met:
Here's how it happened. Vector the crocodile was in the pond or lake or type of body of water swimming when he sensed a threat and came to the surface to see a Dark Legionnaire. He thought it'd be real bright to attack the Legionnaire from behind (not his brightest idea). the Legionnaire quickly defeated him.
Later on that same day Knuckles was with his mentor, Archimedese, meditating and, of course, not focusing. The Dark...