This could just be semantics, but crystal counters would make perfect sense in a Final Fantasy setting
A lot of people are just going to avoid killing a Phoenix if at all possible since it will just come back
Since then, Wizards of the Coast incorporated numbered cards into The Brothers War, where you have the opportunity to open a foil numbered card in Collector Boosters
Harsh Mercy isnt usually going to destroy the creatures youd want it to anyway, and Rukarumel definitely wants to be commanding a different deck and has little to no synergies with this one
Today, there's a fantastic quick start guide available at magic.wizards.com/en/magic-gameplay, and it's easily a better introduction than the Portal rulebooks
I cant recall too many Commander games over the last decade that didnt have a bunch of counters somewhere and it would have been nice to get rid of them