There's no reason why Jin Kazama should not have friends. If you forget about his brooding attitude to life and all its inhabitants, you'd actually see a good-looking, young Japanese man. His passion for fighting and winning the King of the Iron Fist tournament adds an atmosphere that's intoxicating. All you want is to be around him or watch him.
But watching him ticks him off. Being around him makes him brood even more. His attitude gets even worse and worse until you have to leave him alone. If you're someone he hates more than Heihachi (which is pretty hard to come by), you get to be the center of his attention. His fists and feet fly, and unless you train to become bigger, better, stronger, more powerful than Jin Kazama, he will be eyeing your broken and hurt body twist and turn, write and shake, moan and whimper.
The only one he lets close is Ling Xiaoyu. He never intended to have the small Chinese girl get under his exterior. He doesn't even like her that much. She was too cheery, too innocent, too loud, too cute, too sweet. And he hates that. What if someone of that . . . crap rubbed off into him? Will he be cheery, innocent, loud, cute, and sweet? Will that interfere with beating Heihachi? And Hwoarang? And beating the Devil gene?
He supposes he hates the Devil gene. He hates how he relies on the Devil gene when his temper becomes harder and harder to suppress. He hates the pain he feels when his wings sprout and his horns push through his skin. He hisses at the pain, the faint feeling of the pain when he's in his regular state. He will most definitely beat Heihachi.
"JIN! J-IN! Jin! Hello!" Xiaoyu grins cheekily. She keeps waving despite the fact that she already greeted herself. Her pigtails form in, framing her face, making her stand out as her grin gets bigger and bigger as Jin forces himself to look at the cheery, innocent, loud, cute, and sweet girl.
"Miharu and I—well, mostly me—would like to know if you are going to be at the next Tournament? Please? It's never fun without competition!" Xiaoyu squeals. She knows it makes Jin smile when she—a girl who apologizes when she forgets to say 'Bless you'—makes fun of another's ability to fight.
Jin nods. Perhaps Ling Xiaoyu is his friend, if you describe their relationship as friendship. Perhaps he can allow others to be his friend. Perhaps he's not as hard to be around as he thinks.
Hah, that's a laugh.