Official rule text
40.1 Players skip the agenda phase during the early portion of each a When a unit is destroyed, the player who controls that game. After the custodians token is removed from Mecatol unit removes it from the board and places it in their Rex, the agenda phase is added to each game round. reinforcements.
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Source: Twilight Imperium: Fourth Edition - Living Rules Reference: Prophecy of Kings
Expansion: Prophecy of Kings
Version: 2.0
Reference: Rule 40.1