Game:Hayner

In both Roxas' and Sora's stories, Hayner is the first person that you fight in the Struggle mini-game. And the easiest.

Strategy
When fighting Hanyer, there is no particular strategy - the best option is to just hit him and run. It is easier to bash him up, parry his attacks and collect all the orbs before he has the chance to regenerate himself. According to Pence, he also lets his guard down a lot and loses his cool easily. A quick way to beat him as Sora is to use magic at a far distance. Another strategy is to work up a larke combo and finish it with explosion. In Roxas' story, all you have to do is just let it all out on him and make sure you collect as many orbs as you can so you can use them as back up. If he starts getting the better leg of the fight, make sure you collect all your lost orbs as quickly as you can and try to get on top of things. It shouldn`t take long to beat him, and if he defeats you, you need ALOT of practice because you`ll never survive the rest of the game!

Trivia

 * Hayner is one of the few characters fought in Kingdom Hearts II thats not directly related to the Heartless, Nobodies, Disney, or Final Fantasy (others include the Hostile Program and the Experiment). He is also one of four boss characters who is not a Heartless/Nobody/Final Fantasy/Disney Character (adding Riku to the aforementioned list.)