>>40194541"Shillmon", I assume, is the name for a Pokémon that is heavily promoted for a Generation. Some transcend Generation (Pikachu, Charizard, Eevee, Mewtwo, Lucario, etc.) while others are specifically promoted for that Generation (Pikaclones in their respective Generations, starter sets, Croagunk and Buneary in Gen IV, Togepi in Gen II, Sylveon in Gen VI). Starters can transcend Generation, but only when all the first forms are grouped together. Same with Eevee's evolutions. Rarely will you see just Espeon and Umbreon outside their Generation, but you'll see them all together. Piplup gets special focus as the most popular of the first stage Sinnoh starters.
But it's always been like this. Look at the anime main characters' Pokémon in DP. They're all Gen IV, Gen II, or cross-Gen (often between II and IV). Look in Advanced Generation where May got two Kanto starters for FRLG promotion, Munchlax for advanced Gen IV promotion, while her first three Pokémon were standard RS Pokémon. There was no way May would EVER get a Gen II Pokémon unless Gen II promotion was in the cards like with HGSS. Ash got Aipom, but it was late in the series and it was to build up to Ambipom in Sinnoh.
