QD 3atks (Magma Storm)

PH QD 3atks Xerneas should always be either Thunder Cage or Magma Storm, as both moves provide valuable coverage and allow for a semi-consistent win vs. Imposter by partial-trapping them and then spamming Quiver Dance while they get chipped down. Magma Storm, due to its inaccuracy, is the less reliable of the two, but it's still a tremendously powerful move. If you're okay missing sometimes, this set will hit harder than Thunder Cage variants.

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HP is very valuable on this set as there's no recovery move, so Xerneas should be kept very healthy until its HP can be put to a good use. Traditionally this set is used alongside a PH Regigigas, with the very straightforward plan to bring it in against Facade resists. This set is very difficult to hard counter without using an extremely passive Pokemon, so many opposing balance teams will find themselves unable to defend adequately. In particular, the Zap Cannon variant can go so far as to throw out raw Zap Cannons when allowed free entry, fishing for paralyses on would-be counters such as FF/Scales Zamazenta-C, Darmanitan-Zen, and FF Ferrothorn, massively impeding them. Balance teams with sufficient firepower can also try supporting Xerneas with screens.

Modern Xern + Regi is impossible to wall out on a practical level even for the bulkiest teams. Between hazards, paralysis, and basic coverage (all three of which they can run), there simply aren't consistent defensive options. Instead, the best way to beat sets such as this Xerneas is to limit its opportunities through hazards and active positioning. When Xerneas cannot come in without risking a large portion of its HP, its impact on the game will be felt significantly less. For more defense-oriented players, there do exist walls such as Prankster Cresselia, Prankster Type: Null, RegenVest Kyogre, and Flash Fire Steel-types. Though none of these appreciate paralysis, they can accomplish quite a bit by forcing Xerneas off the field as long as their own teammates can win in the meantime.