From Bulbapedia, the community-driven Pokémon encyclopedia.
For the rest of the Battle Frontier arenas, Trainers can use the standard three-Pokémon battle team. However, the Battle Hall's unique methods make it necessary to have a different way of looking at it. I'm trying to provide a guide to help people who might otherwise approach the Battle Hall incorrectly.
The rules of the Battle Hall are simple.
One species of Pokémon is used to continue a streak of as many battles as possible against each separate type. Before each round, the Trainer is allowed to pick which elemental type the next opposing Pokémon will be. This continues for ten rounds at a time, at which point Battle Points will be awarded. The Trainer will continue the streak until either their Pokémon faints or they switch to a different species of Pokémon.
The ultimate goal of going through the Battle Hall is to face (and hopefully win against) Hall Matron Argenta and receive a commemorative print. Note that Argenta will only show up in Single Battle mode.
Some things to keep in mind while making progress through the Battle Hall:
Training the Right Pokémon
The key word is self-sufficiency: If the Pokémon doesn't have the right moves to face a certain Pokémon, it doesn't have a teammate to fall back on (at least in Single Battle mode). Make sure to keep a wide variety of offensive moves to cover the various types.
On a similar note, there really isn't much room for defensive moves on a Pokémon's move roster. Do not hope that defensive techniques can win a war of attrition, because quite often there will be one opponent that can break through a defensive strategy. Focus more on offensive moves, and add status moves if necessary. And always remember to make at least one STAB move fit onto the move roster.
Good move types:
That being said, do not overlook defenses, or in fact any stats, when building up Pokémon for the Battle Hall. For a best balance of stats, use vitamins to max out each stat as evenly as possible. For the stat that can't be raised up as much, choose either Attack or Special Attack, whichever one the Pokémon does not specialize in. If they specialize in both, find a happy medium.
A final note about natures. While a truly skilled Trainer should be able to work with the nature given to them (show flexibility, people!), certain natures' attributes work in tandem. For instance, sacrificing one attack stat for the other, as is the case with Adamant and Modest natures, is not necessarily harmful. It also stands to reason that sacrficing Speed for higher defenses (especially for high-HP Pokémon) and vice-versa (especially for Pokémon with high attack stats) can work.
Typings can trip people up. The big point to keep in mind is that just because a certain type is selected, don't expect the opponent to be purely that type (in fact, for Flying-type, don't ever expect it). It is necessary to prepare for unique typings. Examples of such Pokémon are:
More specifically, a certain type must be paid special attention to: The Steel type!! Due to their 11 type resistances, 1 type immunity, and a related status immunity, special care must be taken to assure that each Pokémon has a move to take care of the Steel menace.
Even more specfically, another one Pokémon must be carefully considered.
Due to its unique ability, Shedinja can make or break a potential competitior. Have the right moves, and its threat goes out the window (along with it), but if no moves affect it, its a race to use Struggle before it KOs any chance of success the Pokémon has of winning (along with it).
That's why its important to have at least one SOS (Stop Opposing Shedinja) move. These can be:
NOTE: Spikes, Toxic Spikes, and Stealth Rock will not work for this purpose!
Two Tips To Try
1. Select a bad type matchup when Argenta arrives. It does not have a bearing on what Pokémon she uses, but it does eliminate one of the harder matchups, especially if at Rank 9 or 10.
2. Persistence is key: This principle is known as "Someday my prints will come".
Pokémon Hall-of-Famers - The Tip Edition
Want to create the ultimate Battle Hall battler? Then use the Pokémon you feel the most comfortable using. Karen wasn't lying. Strong Pokémon vs. weak Pokémon is just a selfish perception of us humans. It's best to work with those Pokémon that you know how to use.
That being said, due to type combinations and other various techniques, some Pokémon do have some advantages when it comes to covering all the types.
Types with one or less weakness
Keep in mind that other Pokémon with these types may also exist.
Other Pokémon who also stand a fighting chance:
||Why they're worth mentioning
||Earthquake beats their weaknesses
||Rock beats its weaknesses
||Ice and Ground cover all problems
||Learns moveset to be discussed later
||Capable of learning the best moves, although perhaps at a stat sacrifice
||Capable of hitting fast and hard with a variety of moves
The combination of the three typed special attacks, combined with an SOS attack (Toxic or Bounce), leave only Empoleon as a resistor and several types covered. As for Empoleon, it has just as much of a problem with Kingdra as Kingdra has with it. If Kingdra is lucky enough (or trained specifically) to get a Fire-type Hidden Power, it can prove very effective at htting Empoleon with neutral effectiveness, while Shedinja still gets hit.
Kingdra should be specially honed in the Special Attack stat. As for items, a Haban temporarily provides a Kingdra with no weaknesses. The Choice Specs or Choice Scarf are good choices as well, depending on which stat still needs some work. Sniper Kingdras should also consider using a Scope Lens, Lansat, or Razor Claw to boost the critical-hit ratio, bringing their ability into effect.
Garchomp has a versatile movepool at its disposal, and because it's a pseudo-legendary, it has the stats to back it up. Chances are, the first movepool listed will be the one more effective, since Garchomp's Attack stat dominates over it's Special Attack. However, in case of Wobbuffet, it might be worth consideration to mix special with physical.
As for the moves themselves: Between Dragon-type and Fire-type moves, only Heatran resists them. Thankfully, under no circumstance does Heatran resist STAB Ground-type moves, leaving all Pokémon open to attack (not to mention Ground has good type coverage anyway). To be honest, Giga Impact/Hyper Beam were added for funsies. If another move fits better with your style, go for it. For example, it you have a personal disdain for Wobbuffet, Crunch might be worth looking into.
Work mostly on Attack and Speed, since these stats are vital for Garchomp. The Yache should help Garchomp last longer against pesky Ice-type moves, but also consider a Focus Sash for overall survivability. The Choice Band or Choice Scarf would also act as good boosters for either necessary stat, provided you know what moves to use.
Torterra happens to have an interesting quirk in its typing: all four types strong against it (Fire, Bug, Flying, and Ice) happen to be weak to Rock-type moves. Therefore, teaching it either Stone Edge or Rock Slide can help it overcome it's weaknesses. Wood Hammer is a strong physical Grass-type move and will act as one of Torterra's two main offenses, along with Earthquake. Crunch rounds out the moveset.
Obviously, Torterra is an attack-oriented Pokémon, so boosting it's attack would be helpful. Also note that Torterra is far from speedy, so bulk up it's defenses/HP to allow it a good chance of surviving an attack or two.
The Yache Berry can help Torterra withstand it's one double weakness, while the Choice Band gives it some extra attack power behind its moves. Alternatively, the Zoom Lens can help Stone Edge become more effective, especially considering how most of the time Torterra's going last.
Coming Fairly Soon (hopefully)... More Pokémon and additional strategies for double battling