Theres already a whopping 16 mainline Final Fantasy games, and dozens of spin-offs released across decades
Esper Sentinel can draw up a handful of cards each turn cycle in EDH, provided that your opponents are playing spells and arent paying their taxes
The player character is the first person to ever give him a challenge which leads to him becoming utterly obsessed with fighting them to the death, to the extent that he fuses himself with a dragon spirit and orchestrates a world-ending catastrophe just to bait you into fighting him. Mechanically, Zenos yae Galvus is a double-faced card that can trasnform into Shinryu, Transcendent Rival
Szadek, Lord of Secrets (~$0.21) is the cheapest genuinely strong mill commander
Instant Color tag templates(None) Blasphemous Act This spell costs less to cast for each creature on the battlefield
And since this would be a Legendary-heavy deck, if and when Aerith dies, she copies all of her counters to every other Legendary on the board