Got a Shadow Ursaluna 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 Shadow Ursaluna, 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: 65W 35L.)
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 15/15/13
You start dropping Latios (Shadow) and similar. If you rarely face them (low real pick rate), it's fine to run.
❌
Don't build yet · Attack 14 or below
Shadow Ursaluna 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.)
65W65%35L
421
777
636
659
514
410
406
486
742
557
500
675
429
681
661
655
500
477
279
742
783
734
630
225
359
783
581
486
665
204
826
540
524
438
235
204
435
461
555
437
706
665
742
559
655
742
840
465
235
268
468
624
644
618
408
460
494
448
575
712
777
500
875
630
548
555
826
720
769
673
516
618
344
604
387
644
728
712
591
681
663
732
259
340
659
600
681
538
769
716
869
583
425
281
465
838
626
540
916
559
⭐ 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) · +5W
⭐
⭐
⭐
⭐
⭐
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 (Shadow Ursaluna vs Shadow Ursaluna)
Mine (atk 14) vs Foe (atk 15)
shields0
Tie
500
shields1
L
487
shields2
L
310
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 Shadow Ursaluna loses that priority to an attack-15 opponent. In the sim, the attack-14 mirror came out 0-shield=tie, 1-shield=loss, 2-shield=loss. In a mirror-heavy meta, attack 15 is effectively mandatory.
Where win/loss starts to split
Shadow Ursaluna is IV-tight. Even dropping to 15/15/13 starts losing Latios (Shadow). 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 5 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 4410 · L51
Best-buddying even a compromise improves every matchup and beats same-stat rivals.
Hundo record by shield count
shields 0
61W · 39L
shields 1
65W · 35L
shields 2
60W · 40L
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 Shadow Ursaluna?
Shadow Ursaluna is IV-tight, so an effective hundo (or very close) is safest. From 15/15/13 you start losing Latios (Shadow). 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'.
