What is your opinion in introducing this character into my story?

[riskingdeath]

I'm writing a story, and I'm trying to introduce a new character into it. Here's the name and the description.

-Kiyoshi Shirukiyo
-Age: 18 even though he acts younger
-Talents/Powers: He can travel through time and tell what will happen in the next hour or so. He can also manipulate aura, which is a type of energy that I imagine to be a little bit purple-ish
-Personality: He's a little bit of a slack off and he LOVES sweets, candy, anything that has sugar in it. He is free spirited and likes to do what he likes to do. He makes up his own rules and is a carefree guy. When he is put in a serious situation, he changes his personality to being strict serious.

He's grouped into the strongest set of people in the universe and has a demonic rival who despises him A LOT. I'm trying to think how he would be introduced into the story. Where I am in the story right now is where two characters are talking to each each other and they're on their way to a base-like building where they're supposed to meet up with somebody. I was thinking of having Kiyoshi walk into the train (the characters are riding on a train, by the way) and he would meet up with these guys. Thing is though, it would be pretty random. How would I fit Kiyoshi into where I am in my story???

Thanks for your opinion!!!! xD
Um, this guy is really supposed to be in the story, and I've had him inside my head for awhile now, but I've just had trouble fitting him in. He plays an important part of the story since the plot is to find out about something. He's a walking history book, so they need him to tell them things about the past.

 

[Jamie]

Maybe, when they get to the building, he can fall from the sky, and fall on top of the people.

 

[yume]

He could be standing on top of the building and all kind of people are surrounding the building. Looking up and pointing at him, thinking he's gonna jump. When the two other characters arrive, he really does jump, but nothing happens to him and all the people start gossiping to each other while he walks up to the two with an "evil" grin. When he reaches them his mood changes completely to this idiotic and fun-loving guy that he actually is and he introduces himself.