No one did. He went there to kill Nicole. He had never needed anyone's assistance to harm her before - there's no reason to think he would have believed he needed to do so that night. The mistakes OJ made, he made BECAUSE Ron showed up. It's always worth pointing out that despite pervasive rumors, Ron was not a 6'1" black belt in karate, he was a 5'9" tennis instructor with no training whatsoever in martial arts. The mistakes OJ made, he made because Ron was there. A neighbor heard Ron yell "Hey! Hey! Hey!" He showed up probably immediately after OJ dealt the first blow to Nicole, knocking her down and rendering her semi-conscious. There was hair from Nicole on Ron's shirt - he must have either not seen the knife or the knife wasn't out yet, and so he would have turned his back on OJ as he went to try to pick Nicole up. And that's when OJ grabbed him. Like a coward. From behind.
We know OJ attacked Ron. Ron pulled off his glove, that's why he cut his finger. It was clearly Ron who did that - the hat and glove were by him. We know those were OJ's gloves, despite the defense antics - Nicole bought them for him, he'd worn them for years. And despite the fact that he was bigger and stronger than Ron (he was several inches taller and outweighed him by at least 40 pounds), Ron still put up a hell of a fight. Unfortunately, because OJ had him from behind, he didn't manage to land any blows - the bruises on the outside of his hands were shown to be from trying to grab onto the tree and the fence. But he did manage to get that glove and that hat.
There's no evidence anyone but OJ was at the scene. Henry Lee is a fraud, that's now thankfully been proven - there were no other footprints there. Only OJ's, in his very rare and expensive shoes. Of all 50ish combined knife wounds, it was what? Maybe 2 that they only couldn't rule out were made by another knife but they also definitely could have been made by the same knife? It'd be a lot more obvious if there really had been two knives. We see one killer - the same man who lost his glove fighting Ron and cut his finger stood over Nicole and killed her too. And that person dropped the other glove at OJ's property, which had plenty of Ron's blood on it. OJ killed Ron. It's POSSIBLE he had a driver, but there's no real evidence to support that either.
