They were used by Pegasus's protg Yako Tenma, who claimed them to be the twins of the three "Egyptian God" cards, and that Pegasus himself was too afraid to produce them, but Yako completed them based on Pegasus's designs
The cards on those parts of the field sharing effects with the Link Monster
Italian Doppelganger Se controlli "Mondo Toon" e un mostro Toon: scegli come bersaglio 1 carta nel Cimitero del tuo avversario
Its able to get its characters out quickly, protect them, and quest for a lot of lore really quickly
They can use those cards to build decks, battle online, or simply view the dynamic range of artwork
Remember that Mega Evolutions function differently from other cards (including EX) in Pokmon TCG Pocket, and reflect the new rules set by the Mega Brave and Mega Symphonia sets in the physical TCG: Knocking out a Mega Evolution card rewards you with 3 points, granting you an instant win in TCG Pocket