Pokemon League of Yellow

After you have defeated all eight Kanto Gym Leaders, you can challenge the Pokemon League (Elite Four/Champion) after making it through Victory Road.

The Pokemon League is comprised of the Elite Four, four of the strongest trainers of the Region. If you should defeat them, you will have the privilege of facing the Kanto League Champion, which just so happens to be your Rival.

Lorelei:

The first Pokemon League Member you will battle is Lorelei. Lorelei is a Water-Type and Ice-Type Pokemon User.

Lorelei's Pokemon: Level 53 Cloyster, Level 54 Slowbro, Level 54 Dewgong, Level 56 Jynx & Level 56 Lapras

After you defeat Lorelei, you can advance to the next Pokemon League Member.

Bruno:

The second Pokemon League Member you will battle is Bruno. Bruno is a Fighting-Type and Rock-Type Pokemon User.

Bruno's Pokemon: Level 53 Onix, Level 55 Hitmonlee, Level 55 Hitmonchan, Level 56 Onix & Level 58 Machamp

After you defeat Bruno, you can advance to the next Pokemon League Member.

Agatha:

The third Pokemon League Member you will battle is Agatha. Agatha is a Ghost-Type and Poison-Type Pokemon User.

Agatha's Pokemon: Level 55 Haunter, Level 56 Gengar, Level 56 Golbat, Level 58 Arbok & Level 60 Gengar

After you defeat Agatha, you can advance to the next Pokemon League Member.

Lance:

The fourth Pokemon League Member you will battle is Lance. Lance is a Dragon-Type Pokemon User.

Lance's Pokemon: Level 56 Dragonair, Level 56 Dragonair, Level 58 Gyarados, Level 60 Aerodactyl & Level 62 Dragonite

After you defeat Lance, you can advance to the Kanto Region Champion.

Kanto Region Champion:

The Kanto Region Champion is your Rival. Your Rival uses a variety of different Pokemon based on what Starter Pokemon you chose.

Rival's Pokemon (Jolteon): Level 59 Alakazam, Level 61 Sandslash, Level 61 Exeggutor, Level 61 Cloyster, Level 63 Ninetails & Level 65 Jolteon

Rival's Pokemon (Flareon): Level 59 Alakazam, Level 61 Sandslash, Level 61 Exeggutor, Level 61 Magneton, Level 63 Cloyster & Level 65 Flareon

Rival's Pokemon (Vaporeon): Level 59 Alakazam, Level 61 Sandslash, Level 61 Exeggutor, Level 61 Ninetails, Level 63 Magneton & Level 65 Vaporeon

After you defeat your Rival, Professor Oak will come and enshrine you into the Hall of Fame. The End Credits will then play, and you will be transported back to Pallet Town. The game, besides the goal of catching every Pokemon, is basically finished.