In official Pokmon TCG rules, you can include up to four copies of the same trainer card in a deck, unless the card itself specifies otherwise
Most Pokmon cards arent very valuable and dont make for great investments
The main difference between the two is Greninja is a Stage 2 that can hit any of the opposing 'mons, even any weakened ones on the Bench
Repeated instances of paying the mutate cost will get expensive (especially with the double blue requirement), but fortunately youre in a color that has some bounce capability
24 packs per box Rarity Collection 5 gives you a special variant art card in every pack, like youve never seen before
UR Ultra Rare Hot Red Dragon Archfiend Bane X DARK Level 10 [ DragonSynchroEffect ] ATK 3500 DEF 3000 1 Tuner + 1 non-Tuner DARK Dragon Synchro Monster You can Tribute 1 monster, then target 1 "Red Dragon Archfiend" monster in your GY