ShowcaseIf Azir, Sovereign is killed or returned to his base before his attack trigger resolves, do token units still move?
If Azir is killed, no token units move; if he is returned to base, no token units move unless he returns to a battlefield before the move instruction executes. Removing Azir does not by itself stop the triggered ability from resolving.407.2407.5 "This battlefield" refers to information drawn from Azir as the ability's source.359.3.f.1 Because Azir's effect does not specify another time, the game checks that information when the instruction executes.359.3.f.2
If Azir is at base or no longer on the board then, he has no battlefield for the instruction to use, so the move instruction is ignored and no token units move.359.3.e.12
A recalled Azir remains the same permanent on the board, so returning him to a battlefield before execution supplies a battlefield for the instruction.457124 A killed Azir moves from the board to the trash.429.2 That card becomes a new object for tracking.124 Returning it to the board therefore does not restore the source tracked by the ability.