On top of being a good card, The Endstone is also a major plot element to Edge of Eternities' story, being the plot device that drives the unique "choose your own adventure" style, as it can rewrite time to achieve what it wants
This card has probably grabbed the most flak, as his effect is pretty lackluster
Prompto Argentum Promptly engaging with haste, Promptos selfie shot ability helps you cast those more expensive spells which will make him important in limited, and maybe even some use in casual or commander decks
Both are powerful, as the first will punch for four damage and then blow up stuff soon, and the later for essentially four damage on a player and then the infect on first strike can drop a foe down to the point that it can't punch back and hurt
Once Ketramose has been declared as an attacker or blocker, it will continue to attack or block that combat even if the number of cards in exile falls below seven