If Grease were more like The Outsiders, Leo (Dennis Stewart), the leader of the T-Birds' rival gang The Scorpions, would engage Kenickie in Mortal Kombat…er, combat. However, this is Grease. So there's no rumbling. Even the fearsome Scorpions appear to be all bark no bite. (Or all whatever noise scorpions make, and no sting.)
Leo acts as an antagonist for Kenickie, which makes us kind of wish that Kenickie were the main character. Danny's biggest antagonist is his ego. Whereas Kenickie has conflict and things at stake if he loses. Leo is the guy who taunts Kenickie, saying,
LEO: I'll give you 75 cents for the whole car, including your chick.
Kenickie love his car, but it's the "chick" comment he cares more about. Yeah, he might like Rizzo even more than his car, which is why she goes out with Leo to make Kenickie jealous. Rizzo is the unspoken prize in the race at Thunder Road, which makes it all the more unfortunate that Kenickie doesn't even get to race. Leo is beaten by Danny, which feels like a hollow victory.