1st edition base set booster box sealed Should I open these original packs? : r/PokemonTCG How would I go about

You can obtain the Heatran (3-Diamonds rarity) card by opening Triumphant Light from Triumphant Light set

however, there are also external factors to consider

Well, of course it has resistance, but this is a strong word

Even after all that, if your opponent does manage to destroy this monster by battle, you can simply destroy the equipped monster instead

To see Aurelia tuned to the max with most of the redundant combos available, give Commander Replays Casual Aurelia deck a look

Like most Pokmon cards, the value of Xerneas depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (BREAKthrough)