Trade it of a gba game or of a cheat
There is not a known Darkrai Action Replay Code for Pokemon HeartGold and SoulSilver yet.
You can't get Darkrai in Pokemon Heartgold. You have to trade it from Diamond, Pearl, or Platinum.
You have to trade from diamond or pearl
Darkrai cannot be caught or encountered in HeartGold or SoulSilver Versions.
darkrai is not in hg or ss,but in fullmoon lsland in Pokemon plantium but requries an item to unlock it.
It is only obtainable through Pokemon Events.
sorry but you can't. you will have to trade it to get it. -RR14
Darkar is not a Pokemon in HeartGold. Darkrai is a Pokemon, but it cannot be bred since it is a legendary Pokemon. You cannot breed dark type Pokemon, either.
You can't unless someone gives you a Darkrai for some other Pokemon you have.
You can only find Darkrai through a Pokemon Event.
Duskull is a Sinnoh pokemon as in pokemon platinum you get darkrai which is the evolution of duskull.
If you downloaded the special Darkrai mission you can transfer it. The special mission has expired and is not available anymore without hacking.