What happens if Shining Jirachi with Choice Band attached uses its "Stellar Reign" attack against an undamaged, evolved, Lucario GX with Focus Sash attached? Does Focus Sash save the Pokemon from a KO?
During the attack Stellar Reign would do 80 damage (10 for the attack plus 30 for the Choice Band, then times 2 for Weakness). Then the devolution part of Stellar Reign would return all Evolution cards to the opponent's hand. However, when KO's are checked the devolved Pokemon is not the same Pokemon that was attacked, so Focus Sash would not protect the newly devolved Pokemon. The original Pokemon took damage from the attack, and the lower Stage just happens to have enough damage on it for a KO.
Source: TPCi Rules Team (2018-05-31)

Relevant cards

Note: All applicable cards may not be listed below.
SM35_42
XY3_91