If people were going to bring in a lot of overly narrow cards like Erase and Stain the Mind, he would transform into a creature deck to dodge these hate cards and take advantage of his opponent's watered-down deck
The commons and uncommons target Limited play, many of them being role players in Modern, with cards like Path to Exile, Electrolyze, and Grapeshot being examples
This isnt the shiniest option of allthat honor belongs to the Special Illustration Rare version from Paldean Fatesbut as a Prize Pack Series card, it might be the rarest
Get ready to get very familiar with the best of them
Priest is a good card in this deck because you can also protect it with Ephemerate or Malakir Rebirth
Perhaps it's an additive thing and Kastral used up many of the copies in circulation, allowing Keeper to spike now