Trade
You have to trade from diamond or pearl
Darkrai cannot be caught or encountered in HeartGold or SoulSilver Versions.
You can't get Darkrai in Pokemon Heartgold. You have to trade it from Diamond, Pearl, or Platinum.
Darkrai can be caught in the following games: Diamond Pearl Platinum
You cannot catch Darkrai in Pokemon Black, you have to transfer it from Diamond, Pearl, Platinum, Heartgold, or Soulsilver.
you get a darkrai in cherrygrove from one of the people.
There is not a known Darkrai Action Replay Code for Pokemon HeartGold and SoulSilver yet.
Darkari is unobtainable in heartgold and soulsilver, only to get it is to trade from pearl, diamond, or platinum.
darkrai is not in hg or ss,but in fullmoon lsland in Pokemon plantium but requries an item to unlock it.
No you can't catch darkrai in ruby unless you hack (witch i do not recommend)
no you do not
You can't catch Rotom in heartgold.