I died then and there itself.
List of clues--
1) The ONLY person Kai speaks to in the entire Manga is Tyson. He doesn't even acknowledge the others at all!
2) When he won the match against Robert, this is what happened...
Kai: I told you I would win.
Tyson: I know, but we're still happy about it!
Kai: *smiles geniunely*
Kai: I don't need you!
Tyson: Why Kai?
Kenny: How do we give Dranzer F to him?
Tyson: No problem Kenny! Since you worked so hard on it, you might as well give it to him! *drags Kenny off to find Kai*
Kai's inner thoughts: Darn it! I cannot lose! I've got to be the world's top blader. So I can defeat Tyson!
5) Kai is in line of Robert's attacks, but Tyson jumps in and takes the hurt.
6) When Kai loses, he and Tyson talk.
Kai: What the heck do you want?
*Tyson hits him*
Tyson: Just returning the favor! Remember what you said to me before? You said"You're stronger than this!" *throws the Dranzer F to Ka. Kai catches it* It's not the end yet! How about it Kai?
Kai: *stares at the Dranzer F*
7) Tyson was hurt and was planning to sit out of training, but he sees Kai train with the new Dranzer F. Hwe stands in front of the door and he says, 'Come on guys, we better train!'
8) The amount of times Tyson says Kai's name is phenominal.
Robert: You have no pride at all in this game.
Kai: you're wrong. *holds up Dranzer F* This beyblade is my pride!
10) When the first round goes to Robert, the Bladebreakers losse hope but then Tyson says--
"C'mon guys! Have a little faith!Kai promised us didn't he? He promised us he'd win!"
11) Daichi and Tyson vs Kai and Tala. When Tala takes advantage of Tyson's weakness, Kai refuese to fight.
"I won't win this way! Not from Tyson!"
12) He taunts Daichi a lot.
"you don't deserve Tyson! You're just a burden to him!"
There's a LOT more, but I think that's enough for you to think about. Kai's obessession with Tyson almost classifies as stalker-type. And Tyson is CONSTANTLY thinking about Kai. Every page, Tyson goes 'Kai!'. Literally.
^___________^ Ah, blessed Tykaness....