Shinto Ruins
From Pokémon HeartGold & SoulSilver Wiki
This is an optional sidequest. To continue the main quest, you may proceed to Route 32 and Union Cave.
The Shinto Ruins (シントいせき) is a small shrine located on a snowy mountain, somewhere far north of Johto and presumably south of Sinnoh.
In order to access the Shinto Ruins, you must have a legitimate Movie 12 Eigakan (えいがかん) Arceus (アルセウス). Hacked Pokémon will not trigger the event.
Before you start, deposit all of your Pokémon into a PC Box at the nearest Pokémon Center, leaving only the Movie 12 Eigakan Arceus in your party. This is very important! You will not be able to complete the event if you have any other Pokémon on your team.
At this point, head off to the blue-roofed Alph Lab in the Ruins of Alph (アルフの遺跡). If you did everything correctly, the researcher should storm out of the house and speak to you on his own. He will take you to the main chamber of the Ruins and start looking at a tile on one of the walls. The screen will flash and you will be teleported to the icy cold shrine.
Now, walk outside and follow the hiker back to his house. Once inside, speak with Cynthia, the champion of the Sinnoh region. If you still have any Pokémon on your team other than the Arceus, this is your last chance to deposit them in the PC. Otherwise, exit the house and head back into the shrine. Suggested that you save right here, or atleast before speaking to Cynthia back in the ruins.
Walk up to the platform and Cynthia will explain that Arceus can create one of three Pokémon: Dialga, the Time-Ruling Pokémon; Palkia, the Space-Ruling Pokémon; and Giratina, the Renegade Pokémon. Each Pokémon will be born at Lv. 1 and you can only choose one of the three. To make your choice, walk up to the circle whose colour matches that of your desired Pokémon. Arceus will create the Pokémon and you will be transported back to the Ruins of Alph.
- Dialga Lv. 1 @Adamant Orb { Special Move: Metal Burst }
- Palkia Lv. 1 @Lustrous Orb { Special Move: Hydro Pump }
- Giratina Lv. 1 @Griseous Orb { Special Move: Shadow Sneak }
Choosing Giratina is the only way to obtain the Griseous Orb in HeartGold and SoulSilver, and thereby Origin Forme Giratina. The Adamant Orb and Lustrous Orb can be held by Dialga/Palkia in Diamond and Pearl and traded over, but the Griseous Orb cannot, as it is automatically removed upon entering the Union Room.
