First of all, it's Kingdom Hearts, not kingdom hearts. Second of all, with a Keyblade and a strong heart with light.
You only get to fight Ansem and his Guardian in Kingdom Hearts and Kingdom Hearts Chain of Memories, while playing as Riku. However, you see the Guardian again when Riku unleashes his darkness to beat Roxas in Memory's Skyscraper.
No, the darkness is just that; Darkness
Kingdom Hearts was created to hold hearts of light and darkness so that a new world can be created, and whoever gets the hearts, designs the world. (As said in the secret reports in Kingdom Hearts Birth by Sleep)
I think you can, but you can fight him in Kingdom Hearts final MixNo
You can't fight Riku in Kingdom Hearts II.
you can't fight Xemnas in Kingdom Hearts 1. you can only fight him in Kingdom Hearts Final Mix. He's a special boss at the end of the game...
Pertaining to Kingdom Hearts, there's no such thing as Righteous Darkness. You may be thinking of Tranquil Darkness, Feeble Darkness, Almighty Darkness, Sleeping Darkness, Looming Darkness, or Bottomless Darkness; all of those are map cards in Kingdom Hearts: Chain of Memories.
No he doesn't. If your referring to the first Kingdom Hearts he will get out of the door to darkness. Sorry if I spoiled it.
The realm of darkness is where Ansem was sealed up at the end of kingdom hearts 1.
At the end of the game in the Land of Darkness, you'll soon meet Riku when he brings Kairi back to you. He'll soon join you to fight and destroy Xemnas. Unfortunately, you can't play as Riku in Kingdom Hearts 2.
The only time Mickey is in Kingdom Hearts 1 is at the end when you seal the door to darkness.
the point is to save all the worlds from darkness...