ARCEUS

Haha, yes, I can help you. In order to obtain the legendary Pokemon Arceus, you will have to do one of three things. One, you will have to go to a Nintendo Event in the future if there is ever one being held near you. Go there, and get the Azure Flute via WI-FI/mystery gift. Two, you can use a cheat code device such as the famous/infamous Action Replay DS, or the Gameshark. After you buy the device, simply put the correct code in, and then you can pick up the item from the Pokemon Mart. Three, find someone that plays Pokemon, and that has an Arceus. See if they would be willing to trade their Arceus to you for some Pokemon that you have. You may have to give them a good Pokemon, or two, so be prepared. As for Darkrai, yes, he looks cool. But, is he strong? If you asked that, my answer would have been no. But still, you should get him if for nothing else, to complete your Pokedex, so go for it. Buy the Action Replay if you want. Hope this helps.

Well with darkrai and arceus you are in the same boat. At this point, if you want them like tomorrow you need an AR. The AR can provide you with the item or the Pokemon instantly, you just have to look up the code in the AR section of this game. In my opinion the potential risk of the AR corrupting your game file is too high to justify getting the Pokemon you want without doing any actual work. It is much more rewarding to catch a Pokemon and raise it. This is obviously not possible with darkrai or arceus, but I just don't feel they are all that good if it simply requires cheating or a special means to get them.

My friend got it from a guy in blue but I forgot where. I know he is in a pokecenter.He was not useing any cheats