Got a Xerneas you've been scraping XL for, and it didn't come out 100%? Before you power up — 30 seconds. We simulated the entire Master top 100 to see whether that spread is fine to build.
For Xerneas, attack 15 is effectively mandatory, and the IVs are tight, so a high catch is safest. Below is the result of running the Master top 100 through a battle simulator, plus the mirror and best buddy. (Hundo 1-shield record: 66W 34L.)
Compromise IVs
15/15/15
IV-tight — an effective hundo is safest. See the verdict below.
Build it or not — at a glance
✅
Just build · 15/15/15 (effective hundo)
This Pokémon is IV-tight — aim for an effective hundo (or very close).
⚠️
Conditional · around 15/15/14
You start dropping Meloetta (Aria) and similar. If you rarely face them (low real pick rate), it's fine to run.
❌
Don't build yet · Attack 14 or below
Xerneas always loses CMP priority to the mirror at attack 14. Don't build it — wait for a better one.
🔬 Full-meta sim — all 100, who you meet & beat
1-on-1 battles vs the Master League top 100, per shield. Green = win, red = loss. (Rating 500 = even; higher = more comfortable.)
66W66%34L
739
329
575
311
883
467
500
402
467
664
379
687
579
361
427
335
593
425
680
655
607
333
536
714
213
824
375
563
393
687
856
726
448
742
883
687
375
833
883
446
448
284
894
502
522
883
357
732
883
737
529
785
500
796
789
260
778
668
557
529
293
883
611
614
484
815
762
760
486
675
465
335
335
872
671
655
833
646
589
627
726
104
657
609
662
404
545
552
473
632
492
522
735
520
684
602
805
335
639
840
⭐ Best Buddy (L51) effect — newly won matchups
Opponents you newly beat once best-buddied. The result depends on whether the opponent is best-buddied too, so both cases are shown.
Opp not BB (L50) · +2W
⭐
⭐
Opp also BB (L51) · +1W
⭐
※ The mirror and same-stat rival return to a tie when the opponent is best-buddied too (both L51). So Best Buddy only wins the mirror when the opponent isn't best-buddied.
Why attack 15 is mandatory — CMP
Attack decides priority. Attack 14 always loses to a same-stat rival.
vsMirror (Xerneas vs Xerneas)
Mine (atk 14) vs Foe (atk 15)
shields0
L
376
shields1
L
461
shields2
Tie
500
Verdict by IV spread (Master League sim)
💡 15/15/15 at the top is the perfect IV (best); rows go to lower IVs downward.
Perfect·Battle-equal= win/loss identical to a hundo (no disadvantage — just use it).
Fine= it only loses to weaker (non-top) opponents, so it's acceptable to run.
N lost= it starts losing to N strong top-10 opponents — a real disadvantage.
CMP loss= at attack 14 you always lose the mirror / same-stat rivals.
‘Matchups lost’ = opponents you newly lose to at that spread (0/1/2 shields = how many shields are used).
Master League has no CP cap, so everyone is max level. When same-species (mirror) or same-stat Pokémon fire a charged move on the same turn, the higher effective attack goes first (CMP). An attack-14 Xerneas loses that priority to an attack-15 opponent. In the sim, the attack-14 mirror came out 0-shield=loss, 1-shield=loss, 2-shield=tie. In a mirror-heavy meta, attack 15 is effectively mandatory.
Where win/loss starts to split
Xerneas is IV-tight. Even dropping to 15/15/14 starts losing Meloetta (Aria). Across the full top-100 sim, small stat cuts cross breakpoints and flip matchups, so a high-IV catch is the safer play here.
Best Buddy — depends on whether the opponent is too
Best Buddy (level +1) depends on whether the opponent is best-buddied. Against a non-best-buddied opponent (L50) you newly win 2 matchups at 1 shield; against a best-buddied one (L51), 1. Top Master legendaries are usually best-buddied, so the mirror and same-stat rivals go back to a tie when both are L51. It never hurts, but it doesn't magically win the mirror.
Note that this line moves with the meta. If usage shifts or a new Pokémon arrives, the breakpoints move and a spread that's fine today can get shaky. This analysis is for Season 28 (2026.09.08~12.01); when the season changes we re-run the full top-100 sim and update it.
⭐Best Buddy (L51) effectBB CP 4326 · L51
Best-buddying even a compromise improves every matchup and beats same-stat rivals.
Hundo record by shield count
shields 0
66W · 34L
shields 1
66W · 34L
shields 2
69W · 31L
Bottom line — attack 15 is non-negotiable (mirror CMP), IV-tight, aim high. Based on the Season 28 (2026.09.08~12.01) meta; updated when the season changes.
FAQ
Q. Do I need a hundo Xerneas?
Xerneas is IV-tight, so an effective hundo (or very close) is safest. From 15/15/14 you start losing Meloetta (Aria). That said, if those losses are low-pick-rate, the real impact may be small.
Q. Attack is 14 — can I just build it?
Not recommended. At attack 14 you lose CMP priority to the mirror and same-stat rivals — a fight that should be 50:50 becomes 0:100.
Q. How long does this hold?
It's the Season 28 (2026.09.08~12.01) meta. When the meta shifts, the breakpoints and the compromise line move, so we re-run the full top-100 sim each season and update it.
Method
BasisSeason 28 (2026.09.08~12.01)ScopeMaster League Top 100Shields0 · 1 · 2Level50 / Best Buddy 51Battle engineGBL Note Simulator (PvPoke-based)Baseline15/15/15Last calculated2026-10-09
✔ Calculated & analyzed by GBL Note
These verdicts come from simulating each spread against the entire Master League top-100 across 0/1/2-shield scenarios with the open-source PvPoke engine. If no matchup flips versus a hundo it's 'Perfect/Battle-equal'; if it only loses to weaker (non-top) opponents it's 'Fine'; once it loses to a top-10 opponent it's 'N lost' by the number of losses. Attack 14 loses mirror priority — 'CMP loss'.
