After completing the Main Story, you can rematch the Champion Cup as many times as you would like. This time around, you can select which opponents will be added to the tournament or if you would prefer a random set of foes. There are twenty-six trainers you can face this time around, including Hop, Leon, Marnie, the eight Gym Leaders, and fifteen Random Pokemon Trainers. Unlike the Random Pokemon Trainers, the Gym Leaders and other Main Characters have stronger Pokemon and each have the ability to Dynamax/Gigantamax one of their Pokemon.
Melony, of course, is one of the eight Gym Leaders you can face in Pokemon Shield when rematching the Champion Cup. Melony still focuses on using Ice Type Pokemon, having Frosmoth, Mr. Rime, Eiscue, Galarian Darmanitan, and Larpas when in battle. All of Melony's Pokemon will be between Levels 60-62, and she'll always Gigantamax her Lapras. Because of this, Melony is still weak against Fire Type Pokemon & Attacks. Melony continues to also struggle against Rock Type and Steel Type Pokemon & Attacks, since most Ice Types are extremely weak against them as well.
After defeating both the Isle of Armor and Crown Tundra DLC Packages, Melony's Champion Cup Rematch Pokemon Team will have changed slightly. All of her Pokemon will now be at higher levels.
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