For starters, the front side of Kefka is a totally fine Commander by itself
This game mechanic is detailed in the Master Rule (1 April 2020 Revision) under which states that If a card moves location from its activation location to a different location before its effect is activated, its effect cannot be activated (including mandatory effects)
Those become your libraries in the main game, which then resumes from where it left off, with The Countdown Is at One finishing resolving
This card is particularly situational, and not that great when the situation comes around, but its one of the oldest humble-adjacent effects in the game, and I feel like I could write an entire D&D campaign based on that flavor text
Please use it as a tournament deck if you like
Incapsula incident ID: 1292000700180765122-546018071438692747