Spoiler: 3-4C Mythopoeic Curse found

[elcoderdude]

The Mythopoeic Curse is hidden in the cards for Mummy's Mask.

This is an interesting and very solvable puzzle, so do not look at the links below if you want to solve it yourself. (Or, just look at the hint.)

Hint from Vic:

Hint from Vince
Note the (not-relevant) links to other puzzles in that post seem to be broken.

Solution from community:

Solution thread

Mike Selinker said he would write a blog post about this soon. It seems strange if he would give away the secret, so he probably won't, but if you want to solve this completely on your own, you may want to act soon.

[Mike Selinker]

I have written said blog. Depending on the schedule, it might appear next week, and it might not. (This is not a riddle.)

[Vic Wertz]

Next week will be Shannon's new strategy blog—the puzzle blog will run the week after.