I don't think you can battle Gardenia in Pokemon HeartGold.
let your Pokemon battle
No they can't.
She is a Sinnoh gym leader, the game is based off the regions of Johto and Kanto.
No, you can't battle Maylene and/or Crasher Wake in Heartgold.
Get the celebi event.
No they can't.
let your Pokemon battle
She is a Sinnoh gym leader, the game is based off the regions of Johto and Kanto.
No, you can't battle Maylene and/or Crasher Wake in Heartgold.
Ash is not in Pokemon HeartGold, but Red is able to battle on the Summit of Mt. Silver.
No you can't
you dont.
yes or no you choose
You can't battle Steven in Pokemon HeartGold.
You can't battle Steven in Pokemon HeartGold.
y-y-yes
no. Pokemon battle revolution can only take Pokemon from diamond/pearl