Correct. CMC is one of the parts of a card that does not change. The only exception to that are spells, while on the stack their CMC is + the rest of their cost and while not on the stack the is zero. Otherwise CMC does not change.
May 16, 2018 1:43 p.m.
Thanks, I didn't think I was wrong I just ketp seeing it and things like it in Jodah decks and was confused.
May 16, 2018 1:54 p.m.
Not 100% accurate, as both Fuse and Aftermath cards can have their CMC change.
While in any zone other than the stack, their CMC is equal to both halves of the card. While on the stack, it is equal to the half being cast (or both if fused). This is a change from the old rule, and was implemented in Amonkhet.
May 17, 2018 1:19 a.m.
A fun interaction with Jodah, Archmage Eternal and Fist of Suns are cards like Painful Truths which care about how many colors you spend on the spell. Normally painful truths only draws at most 3 cards, but with either Jodah or fist, you would draw 5 cards.