Rowdy is Arnold's best friend, arch nemesis, and everything in between. And, as his name indicates, he's a pretty tough guy... most of the time.
Rowdy The Best Friend
This guy is your typical hooligan with a heart of gold. He's full of swagger, but he has a heart that is softer than a package of Starburst that's been left in the glovebox all summer. Oh yeah—and he's a nerd:
But before you think Rowdy is only good for revenge, and kicking the shit out of minivans, raindrops, and people, let me tell you something sweet about him: he loves comic books. But not the cool superhero ones like Daredevil or X-Men. No, he reads the goofy old ones, like Richie Rich and Archie and Casper the Friendly Ghost. Kid stuff. He keeps them hidden in a hole in the wall of his bedroom closet. Almost every day, I'll head over to his house and we'll read those comics together. (3.114-3.115)
We feel you, Rowdy. We all do embarrassingly nerdy things that make us feel good when the world seems like one long Monday afternoon: our nerd-routine involves watching The Fox And The Hound and hula-hooping.
But Rowdy also definitely lives up to his nickname. He sticks up for Arnold... but he also pushes Arnold around from time to time. This isn't totally Rowdy's fault—he's from a family with a history (and practice) of domestic abuse, and he's a pretty damaged kid with a completely understandable impulse to lash out. He's also pretty scared by the prospect of abandonment, and having his bestie move schools hits him like a slap in the face.
Or maybe we should say it hits Arnold like a slap in the face:
"Why are you leaving?"
"I have to go. I'm going to die if I don't leave."
I touched his shoulder again and Rowdy flinched.
Yes, I touched him again.
What kind of idiot was I?
I was the kind of idiot that got punched hard in the face by his best friend.
Bang! Rowdy punched me.
Bang! I hit the ground.
Bang! My nose bled like a firework. (7.64-7.72)
Rowdy's never felt as though he's been safe. So when he's faced with yet another abandonment, he does what comes naturally to him—he gets punchy.
Rowdy The Arch Nemesis
Rowdy becomes Arnold's worst enemy—or maybe it's the other way around. Arnold gets the silent treatment from Rowdy, and he also gets more than he bargained for when the two face off at the Reardan/Wellpinit basketball game.
But by the end of the novel they reach an understanding. Part of this comes from the fact that Rowdy realizes that Arnold isn't actually going to leave him behind. And part of this comes from the fact that Rowdy realizes that Arnold's first priority has to be Arnold:
"So, anyway," he said. "I was reading this book about old-time Indians, about how we used to be nomadic."
"Yeah," I said.
"So I looked up nomadic in the dictionary, and it means people who move around, who keep moving, in search of food and water and grazing land."
"That sounds about right."
"Well, the thing is, I don't think Indians are nomadic anymore. Most Indians, anyway."
"No, we're not," I said.
"I'm not nomadic," Rowdy said. "Hardly anybody on this rez is nomadic. Except for you. You're the nomadic one."
"No, I'm serious. I always knew you were going to leave. I always knew you were going to leave us behind and travel the world. I had this dream about you a few months ago. You were standing on the Great Wall of China. You looked happy. And I was happy for you." (30.176-30.184)
Rowdy realizes that Arnold needs to move around; wanderlust is part of what makes Arnold Arnold. But the way Rowdy expresses this sentiment makes it obvious that Rowdy isn't ticked off with Arnold—and, more importantly, doesn't think that Arnold has abandoned his heritage. Rowdy shows Arnold that he still thinks of him as Indian... which is another way of showing Arnold that he thinks of Arnold as being part of his life.