When challenging the Galarian Star Tournament, you will eventually have the choice between seventeen different trainers to Pair with or face off against. No matter whether you pair with them or they oppose you, their Pokemon teams will never change. One of these seventeen trainers is none other than Klara (if playing Pokemon Sword), your Rival on the Isle of Armor, and she will always bring into battle Level 68 Galarian Slowking, Level 69 Scolipede and Level 70 Galarian Slowbro that will be able to Dynamax.
No matter what Pokemon you use, it would be smart to have higher leveled Pokemon when facing the Galarian Star Tournament. Because Klara specializes in using Poison Type Pokemon, her Pokemon are especially weak against Ground Type Moves. With all of that said, however, it really doesn't matter what Pokemon you use as long as they are at incredibly high levels. As long as your Pokemon aren't weak to certain other Pokemon Attacks, a Level 90-100 Pokemon will usually handle any Level 70 Pokemon with ease.
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