I just realized...

So, I read through Garen's lore and I just noticed something. It says here that

'It was beneath their mighty banners of war that Garen first met steel with Katarina, the Sinister Blade. The infantrymen who beheld this event (and survived) commented that it seemed as though the two were locked in a mortal waltz set against a symphony of clashing blades.' - Garen/Background

Garen doesn't have anything that would particularly look like a 'waltz' except for his spin attack, and that's kind of the same with Katarina. That means that in that fight, all they were doing was spinning at each other really fast.

League of Beyblades? :|