I'll analyze the winrate of Azorius Control with and without Yorion in the sideboard since November 10th in Pioneer.
Now let me query the database to find Azorius Control entries in Pioneer since November 10th and compare performance with and without Yorion in the sideboard:
The query returned no results. Let me check if there's any Azorius Control data in Pioneer for this time period:
Good! Azorius Control is present in the Pioneer meta. Now let me query for the Yorion split with the correct archetype ID mapping:
Now let me run the performance analysis with the correct Pioneer archetype ID:
Great! Now let me check companion usage in the entries without Yorion to see if they're using Kaheera:
Since November 10th in Pioneer, Azorius Control with Yorion in the sideboard has posted a 61.8% winrate (21-13 excluding draws) across 9 entries, compared to 54.9% (112-92) for the 45 entries without Yorion. The Yorion builds show a 6.9 percentage point advantage, though the sample size is relatively small.
Your assumption about Kaheera is mostly correct: 87% of non-Yorion Azorius Control lists (39 of 45) are running Kaheera as their companion. The remaining six entries appear to be running no companion at all. The Yorion version's stronger performance is notable but should be interpreted cautiously given the limited data - just 9 Yorion entries versus 45 Kaheera/no-companion entries.
Sources: Data from 22 tournaments: 86.4% MTGO, 13.6% Melee. Recent examples include:
https://www.mtgo.com/decklist/pioneer-challenge-32-2025-11-2912825478
https://www.mtgo.com/decklist/pioneer-challenge-32-2025-11-2812825463
https://www.mtgo.com/decklist/pioneer-challenge-32-2025-11-2812825456