Xerneas @ Toxic Orb
Ability: Poison Heal
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Moonblast
- Quiver Dance
- Rapid Spin
- Strength Sap
One of Zygarde-Complete's main weaknesses is dragon. The popularization of Reshiram and Palkia as anti-meta pokemon has also similarly lowered the viability of Zygarde-Complete, because these pokemon often carry adaptability Dragon Energy which can KO Zygarde-C. Xerneas offers an invaluable Dragon immunity for Zygarde-C, so that Xerneas can tank Dragon Energy's for Zygarde-C. A timid nature ensures that when Xerneas switches in on these pokemon it an also shrug off the next attack, by quiver dancing up before they get to launch water spout or dragon energy, or by clicking strength sap on a predicted fishious rend or V-create. Fairy / Dragon / Steel is also one of the best defensive cores in BH, and Xerneas + Zygarde-C form an extremely strong start to this. Xerneas is also able to cover for Zygarde-C's weakness to Glance. Currently, some of the most potent physical breakers are Groudon, Landorus-T, and Kyurem-Black. A timid nature on Xerneas allows it to outspeed both these pokemon and click strength sap on Glance, and because of its large HP stat, Xerneas will also live most Groudon & Londorus-T band-adaptabilty Precipice Blades, allowing it to Strength sap on the next turn and heal to full, while also dampening the power of the move.
Xerneas is also able to compliment Zygarde-C with its extremely high pp. Xerneas on its own has 136 pp, which allows it to pp stall a plethora of pokemon, and strength sap allows it to outstall anchor shots which would KO it. Zygarde-C has 144 pp which allows it to trap and pp stall many foes. Together, with a total of 280 pp, they form a really strong core against stall. Their really high pp means that very few pokemon can trap the, and effectively make progress on either of them and they can work in tangent to pp stall, by Zygarde-C threatening to trap a foe a pp stall, and Xerneas by virtue of forcing Ice Scales / Prankster pokemon in because of the threat it carries with moonblast.
The meta has not been kind to Prank Zygarde-C. It is no longer the formidable pokemon it was in Gen7bh. It's resistances don't really attribute much to a team, as Rock and Poison moves are seldum seen. Similarly, the best fire pokemon is Reshiram, which Zygarde-C does't want to switch into because of its secondary Dragon typing. Also, Zygarde-C's weaknesses have been accentuated this gen, as Ice and Dragon moves have been buffed because of the introduction of Glance & Dragon Energy. Zygarde-C can also be a hindrance to many teams because it fails to do much as a support pokemon or make pragress, and due to these weaknesses is often a liability to many teams.
This Xerneas set is able to best cover a lot of these weaknesses listed by its ability to be non-passive with qd + moonblast, it's ability to be a strong support pokemon w/ rapid spin (Giratina can't really spinblock it), and its ability to support Zygarde-C's weaknesses to Dragon & Glacial Lance. This is why this Xerneas set is able to form a strong partnership with Zygarde-C.