How do you get the golden keyblade in Kingdom of Hearts 2

okay I don't know what you're talking about this "Golden Keyblade" unless you have some funky Japanese version...BUT if you want to know what all the keyblades are (For the American edition) go to www.gamesradar.com (Cheat website) and scroll down the page checking out the hints and all that and somewhere on that page is a list of allllllllllllll the keyblades and how you get them.
Now if you have the final mix or some other wierd type of KH2, just go Google, swagbucks, or yahoo, and just type in "List of keyblades for KH2 Final mix" or whatever version you have :D So there ya go! I do hope I helped you (Take this from a master at Kingdom Hearts!)

Hey. Neku here. To unlock the Golden Keyblade known at Kingdom Key D(Darkness), you must complete Jiminy's Journal in it's entirity. After you do, you must go to the Timeless River. You should see another Monorail. Enter it. Once you do, you'll see King Mickey, and you have to help him defeat the Heartless. After you do, you'll get his Summon Charm. After that, summon him with "I won't give up!" and he should appear. Use him and after the battle, you should have Kingdom Key D.