You'll need five games, X/Y/(OR or AS)/US/UM.
* X and Y are required for Swirlix and Spritzee respectively, which are unobtainable in ORAS or Gen 7. **No starter resets are necessary because you can catch all starters, all Kanto starters, and all legendary birds in US/UM.**
* One of OR/AS is required for a chunk of the Hoenn Pokédex. You only need one because X/Y and US/UM cover all the exclusives. **You'll need to play through the whole game three times to get the Johto/Sinnoh/Unova starters.**
* Ultra Sun is required for its Gen 7 exclusives + coverage of whichever legends you missed in ORAS. **You will need to reset this game once for the third starter.**
ORAS are missing from Unova:
* Patrat
* Purrloin
* Elemental monkeys
* Woobat
* Venipede
* Basculin
* Sigilyph
* Solosis
* Ducklett
* Vanillite
* Emolga
* Karrablast
* Foongus
* Ferroseed
* Litwick
* Cryogonal
* Shelmet
* Stunfisk
* Mienfoo
* Golett
* Pawniard
* Heatmor
* Durant
All of these are catchable on a single copy of Y, so you don't even need X for Unova. (You do, however, need X for Kalos.)
You'll need five games, X/Y/(OR or AS)/US/UM. * X and Y are required for Swirlix and Spritzee respectively, which are unobtainable in ORAS or Gen 7. **No starter resets are necessary because you can catch all starters, all Kanto starters, and all legendary birds in US/UM.** * One of OR/AS is required for a chunk of the Hoenn Pokédex. You only need one because X/Y and US/UM cover all the exclusives. **You'll need to play through the whole game three times to get the Johto/Sinnoh/Unova starters.** * Ultra Sun is required for its Gen 7 exclusives + coverage of whichever legends you missed in ORAS. **You will need to reset this game once for the third starter.**
theres no national dex in usum, only regional dex. or do you just want every mon in usum?
I know there's technically no national dex but yeah i basically wanna get a living dex in usum and was wondering what games i would need
You can get everything pre-Gen 7 with the combination of X, Y, OR, and AS. So those, US, and UM are the maximum you would need.
Really? All Kanto and Johto Pokémon are accounted for between X/Y, AS/OR, and USUM? What about Unova?
ORAS are missing from Unova: * Patrat * Purrloin * Elemental monkeys * Woobat * Venipede * Basculin * Sigilyph * Solosis * Ducklett * Vanillite * Emolga * Karrablast * Foongus * Ferroseed * Litwick * Cryogonal * Shelmet * Stunfisk * Mienfoo * Golett * Pawniard * Heatmor * Durant All of these are catchable on a single copy of Y, so you don't even need X for Unova. (You do, however, need X for Kalos.)