When those cards are anywhere else (in your hand, your deck, your discard pile, or as your Prize cards), each card is treated as one separate card
LEGEND Pokmon are printed across two cards, which need to be laid side by side to display the full nature of the art & mechanics
Credit: Wizards of the Coast Mindslice Apparatus BPhillipYork: So instant and sorcery reduction that increases over time is pretty good, flashing it in right before your upkeep is strong
Unfortunately, this led to some crucial cards for popular archetypes being nearly impossible to obtain before a proper reprint, and that is precisely what happened with the first printing of one of the best XYZ monsters, Minerva, the Exalted Lightsworn
This all comes down to their pull rates