Why can't I transfer my Pokemon?

I was transferring my Pokemon from Pokemon Pearl to Black, and from Black to Y. However it wouldn't transfer my Arceus, Giratina, or Darkrai. What happened?
Their names are GodDeer, GhostDrake, and Nightmare respectively - Were the names not allowed?
Best Answer
Assuming that you Pokemon are legal. I believe this answers your question. The following was taken directly from the Pokemon Bank FAQ:
All the Pokémon that appear in Pokémon X, Pokémon Y, Pokémon Omega Ruby, or Pokémon Alpha Sapphire that can be deposited in Pokémon Bank. However, there are some Pokémon that you will find yourself unable to bring into Pokémon X, Pokémon Y, Pokémon Omega Ruby, and Pokémon Alpha Sapphire using Pokémon Bank and Poké Transporter.
- Some Pokémon cannot be transferred from the GBA games Pokémon Ruby, Pokémon Sapphire, Pokémon Emerald, Pokémon FireRed, and Pokémon LeafGreen to the DS games Pokémon Diamond, Pokémon Pearl, Pokémon Platinum, Pokémon HeartGold, and Pokémon SoulSilver using the Pal Park feature.
- Some Pokémon cannot be transferred from Pokémon Diamond, Pokémon Pearl, Pokémon Platinum, Pokémon HeartGold, and Pokémon SoulSilver to Pokémon Black, Pokémon White, Pokémon Black 2, or Pokémon White 2 using the Poké Transfer feature.
- Some Pokémon from Pokémon Black, Pokémon White, Pokémon Black 2, and Pokémon White 2 cannot be transferred to Pokémon X, Pokémon Y, Pokémon Omega Ruby, or Pokémon Alpha Sapphire.
Which Pokémon can or cannot be transferred depends on the settings of each game, so this information cannot be provided here. Please try transferring your Pokémon to confirm their eligibility for yourself.
Pictures about "Why can't I transfer my Pokemon?"



Why cant I transfer some Pokémon to lets go?
Only the Pok\xe9mon you've caught in Pok\xe9mon GO that were originally discovered in the Kanto region (as well as their Alolan variants) may be transferred. You can't transfer Pok\xe9mon from Pok\xe9mon: Let's Go, Pikachu! or Pok\xe9mon: Let's Go, Eevee! to Pok\xe9mon GO.Can you still transfer Pokémon?
Yes, you can transfer all your Pokemon to Pokemon Home from as far back as the Game Boy Advance games.No No! Why Can You Come Back, My Toys? - Wolfoo Kids Stories About Toys | Wolfoo Official Channel
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Pixabay, cottonbro, Karolina Grabowska, Mnz