The idea looks nice. Personally love the thought put on the mitigation factors for the most obvious broken combo.
The upgraded one looks a bit too math heavy though. The N=sqrt(cost) could be changed for a catapult-like text (I know it's more text, but it'd look better). IDK how to solve the text overload, maybe the M part could be obviated?
"patience brings victory" sounds more like a elemental proverb to me
Also, a less math heavy solution for the upped version could be: " kill the 2 cheapest enemy creatures"
If only I had more space...
The cost relation is mainly a way to make more powerful creatures harder to kill. The real emphasis for this skill is that it kills every marked creature eventually .... I actually wanted to name the skill 'Death Note' (in honor of the anime) i.e. 'their days are numbered' sort of theme.
So just outright killing the two cheapest creatures immediately isn't what I was aiming for. It would also make killing very powerful creatures a little to easy against non-swarm decks..
I could, of course, go with just using N=cost, but that makes it essentially useless against anything that costs more than about 5 quanta.
Hence, I went with square root, which scales up realtively quickly at first and then slowly later on.
Wish I had one more line to work with. If so I would change the text to: "Marked enemies will now die in a number of turns based on their cast cost"