Let me look up both the Boros Energy archetype and the Ranger-Captain card simultaneously!
Here's the breakdown for Ranger-Captain of Eos in Boros Energy over the last 30 days:
Ranger-Captain of Eos — Boros Energy (Feb 9 – Mar 11, 2026)
So roughly 3 in 4 Boros Energy players are running Ranger-Captain. It's clearly a strong-but-not-universal include — likely acting as a toolbox piece fetching 1-mana creatures like Ragavan or Voice of Victory while doubling as a counterspell lock via its sacrifice ability.
The ~27% not running it tend to skew toward more streamlined or Blood Moon-heavy builds that trim the 3-drop slot.
Sources: Data from 94 tournaments (last 30 days), ~74.5% MTGO / 25.5% Melee.