How To Beat Dark Rust
Dark Rust is the final boss. What you have to do is run around until Cobalion smashes his shield. It will take about 2-3 seconds, so stay away. He is one of the easiest bosses in the game.
How To Beat Cobilian
First of all, you don't. What you have to do is get 3 of your strongest, then you die. Cobilian will kick you to Westerly town.
Choosing Your Favorite Pokemon
When you press x to select your pokemon press r to put the pokemon as your favorite Note: It will be the top choice of your pokemon selection.