Free Comic Book Day took place on May 5th, 2018 and featured the Mighty Morphin Power Rangers Shattered Grid tie-in special issue. This issue became incredibly hard to find as the mega-event Shattered Grid had just begun with shocking twists a couple of weeks prior.
Zordon communes with the Emissaries, the gatekeepers to the Morphin Masters. He seeks both their guidance and appeals for their assistance in dealing with Lord Drakkon, the alternate reality timeline Tommy Oliver who voluntarily chose to be evil, who has traveled to the current reality and timeline and killed our Tommy Oliver.
This issue is by no means required to enjoy the mega-event Shattered Grid however these characters are part of the larger story towards the end. Kyle Higgins does an excellent job expanding the mythology and the lore of the Power Rangers universe with their introduction and, in the end, their reasoning for what they choose, and choose not, to do.
Cover image below.