Arlo is one of the three Team GO Rocket leaders in Pokémon GO. You can find them by defeating Team GO Rocket Grunts at captured PokéStops. You’ll need to find six mysterious components to create a Rocket Radar. You can equip it from your bag and use it to locate one of the leaders. When you find Arlo at a Leader Hideout, you need to defeat them to clear out the hideout.
Arlo now has three Pokémon in their line-up you need to defeat during the battle. You have a handful of options available to you to fight him, so make sure you keep a rotating roster of compelling choices to use during the engagement.
The first Pokémon is Mawile, which is a Steel and Fairy-type. To defeat this Pokémon you want to use a Fire or Ground-type Pokémon, such as Darmanitan, Flareon, Arcanine, Excadrill, or Rhydon. Any of these options would work against Arlo’s first Pokémon, but you may want to choose a more durable Pokémon rather than relying on the pure attack of your first option.
The second Pokémon in Arlo’s roster can consist of Charizard a Fire and Flying-type, Blastoise a Water-type, or Steelix a Steel and Ground-type. All of these Pokémon vary in their types, making it a little challenging to know the best approach to prepare to fight any of these three.
Your best bet might be to rely on a Water-type Pokémon. While they are not effective or stable against Blastoise, you can have them use different moves than Water-type to damage it, and also use these typings to take out Steelix or Charizard if you fight them. For Water-types, you can choose between Gyarados, Vaporeon, Milotic, Swampert, Feraligatr, or Kingler. There are a wide variety of Water-types to pick from to use in battle.
Alternatively, an Electric-type also works against both Charizard and Blastoise, which means you could use Magnezone, Jolteon, Ampharos, or Electabuzz. The downside to using an Electric-type is the fact they’re going to be extremely weak against Steelix. You may only want to use one if they have a secondary attack they can reliably use against a Steelix.
The final Pokémon Arlo could use against you is Dragonite, a Dragon and Flying-type, Salamence a Dragon and Flying-type, and Scizor a Bug and Steel-type. You have a bit more consistency here than you did with the other Pokémon choices.
Dragonite and Salamence share the same typing, so you can use a Dragon, Rock, Fairy, or Ice-type during this fight to bring them down pretty fast. You can choose to take Garchomp, Flygon, Gardevoir, Clefable, Lapras, or Cloyster. Any of these options would be good against these two.
While Scizor is a Steel-type, they are resistant to Dragon, Fairy, and Ice-types, but not Rock-type. You may want to rely on a Pokémon with Rock-type abilities or a Rock-type to fight any of these three, such as Armaldo, Kabutops, Solrock, Lunatone, or Probopass.
You’ll have to think about what type of Pokémon you want to use against any of these different sets. You want to use a general moveset of attacks, focusing on what is resistant to the Pokémon to have yours last the longest. It’s tempting to find a Pokémon that can consistently use super-effective attacks, but Arlo’s roster comes with quite a bit of health.
It’s a game of attrition, with you wanting to last as long as possible. The higher defense and overall resistances your Pokémon has, the longer you can stay in a fight.