I love the mechanical flavor of the embodiments - growing stronger with devotion/belief is awesome!
A couple of thoughts about design:
- the denounce on Write on Earthenware doesn't work, since the spell doesn't target anything - the ETB trigger targets, but by then costs have been paid and the spell has resolved.
- A card called Sleep Paralysis already exists! See
Sleep Paralysis. Your version is significantly stronger, but IMO probably still fine if there is more than average enchantment removal (and noting that
Paralyzing Grasp also exists)
- The power level on the legendary spells seems all over the place: white seems unplayable, even in a planeswalker heavy meta like War of the Spark, due to the hoops you have to jump through to make it do anything, and even then it seems too narrow; blue seems significantly stronger (see
River's Rebuke or
Flood of Tears, and assuming you aren't against a token deck or the like) - noting that you need a legend in play to cast the spell, this seems to me to be the power level you should shoot for. Black is again very narrow (except against tokens..) - compare to
Finale of Eternity, which doesn't require a legend, can hit more targets on average, and scales. Red reminds me of
By Force - even assuming you will have an enchantment most of the time, you still need a legend, and it only shaves 1 mana off the cost. Green is back to being very strong, and IMO about where you want these spells, if not a little too strong.
That ended up being a lot more than I expected.. I'm new to custom cards, so feel free to disregard any or all of the comments, but I'd be curious to hear your thoughts!
Looking forward to seeing more cards!