In this challenge the aim is to defeat the champion of which-ever region you are in without using any pokemon that were originally introduced into that region. You begin the game by trading your starter for something else as soon as you possibly can or catching something native to another region as soon as you can and then proceed throughout the game without ever catching a pokemon introduced in the region you are playing.
Example: If you are playing Black 2 as soon as you are able to you either trade over a pokemon introduced in Gens I-IV or capture one of the many pokemon not originally part of the Unova Regional Dex.
This challenge is relevant to G/S/C, R/S/E, D/P/Pt, B/W and B2/W2. Clearly it will be impossible in Gen 1 unless you hack them in on a ROM. Which you may if you notify people that you intend to "cheat".
Replace your starter with a "legal" pokemon ASAP
Do not use any "illegal' pokemon on your team
The challenge is over when you defeat the regions champion (in terms of the challenge)
You may use trades
You may use HM slaves that don't match the description
You may use a pokemon that evolves into something introduced in a different generation.
You may not use a pokemon from your chosen regions introduced pokemon that evolves from a pokemon of a different generation but you can use their prevolution.
You complete the challenge when you fulfil these conditions
Johto (Easy) - Defeat the Johto League
Johto and Kanto (Hard) - Defeat Red
Hoenn (R/S) - Defeat Steven
Hoenn (Emerald) (Easy) - Defeat Wallace
Hoenn (Emerald) (Hard) - Defeat Steven
Sinnoh (Easy) - Defeat Sinnoh League
Sinnoh (Hard) - Defeat Barry once at the Battle Tower
Unova (B/W) - Defeat Alder
Unova (B2/W2) (Easy) - Defeat Iris
Unova (B2/W2) (Hard) - Defeat Alder
*Note: Easy and Hard challenges can be completed in the same run without starting again.
1. If you are looking for a more difficult version of this challenge you can try to complete the challenge with a mono-regional team (ie. All team members introduced in the same Gen).
2. Do this as an ultimate challenge by completing this challenge across games from each region (bar Kanto only games).
"Starter": If doing this as an Ultimate Challenge just update per game.