Gateway Colosseum

The Gateway Colosseum is a great place to start things out. In the Gateway Colosseum, you can only use Rental Passes, which are preconfigured Battle Passes that are equipped with six various Pokemon and a bit of strategy to fit each one of them. In order to earn Rental Passes and use them outside of the Gateway Colosseum, you'll need to conquer it first. Afterwards, you can use the Rental Pass wherever you'd like.

At the start, there are only two Rental Passes to choose from, but as you progress through the game, you'll be able to select more to use here.

All of the videos and strategies shown here are using the Blue Pass, because I think it is a little bit better than the Red Pass (but maybe that's just my battle style).

The battles here will all be at Level 30, and each of the 7 Rounds will be a Single Battle against another Trainer.

Monferno makes a great Pokemon to start with in this fight, because it will have an advantage against all of his Pokemon, with either Mach Punch (against Spinda and Lickitung) or Fire Punch (against the others).

Again, Monferno is a great Pokemon to use in this round, due to its potent Mach Punch attack, which is Super Effective against all of Alec's Pokemon.

Things are a little bit more diverse in the third round due to there not being a specific weakness to exploit. Prinplup would probably be your best choice to start with. Be leery about using Rain Dance, though, as Lombre will take advantage of it (although it won't help it out too much, as Pluck will be effective against it).

Monferno is once again a great choice to use here. Mach Punch handles Loudred, Fire Punch takes out Silcoon, Kakuna, Delibird, and Sunflora, and Grass Knot will put Rhyhorn in its place. Just as long as it doesn't get knocked out by Delibird's Aerial Ace attack, you should have no difficulty.

This one is another difficult one to decide who to start with. Monferno and Staravia are probably your safest bets here for starting. None of the Pokemon should be too difficult to take out. Just make sure you switch to an appropriate counter if you don't think your current active will cut it.

Grass- and Bug-type Pokemon are all over this fight. Starting with Monferno is probably your best bet, since it should be effective against 4 of their Pokemon. Just be cautious around Yanma, because it is fast and can use Aerial Ace. Sableye and Farfetch'd are probably better handled by your other Pokemon.

Joe is the Colosseum Master of the Gateway Colosseum. Although the Pokemon on his team are all unevolved, they have rather strong moves. Monferno and Luxio offer the best type coverage, with each able to handle three of Joe's Pokemon. Monferno can take down Spinda with Mach Punch, and Treecko and Delibird are both weak to Monferno's Fire Punch. Luxio's Spark is effective against Drifloon, Mudkip, and Delibird, plus, since all of Joe's Pokemon (except for Delibird) are Male, Luxio's Rivalry Ability will increase the damage you do against them. Prinplup would probably be a good third Pokemon to have on your team against Joe.