Rather than pumping up the army of Nazgl, Witch-King, Bringer of Ruin is simply just a great card in Commander
There are so many new decks to explore you know, since theres effectively a sixth color.
Creature Sephiroth, One-Winged Angel Flying Super Nova As this creature transforms into Sephiroth, OneWinged Angel, you get an emblem with "Whenever a creature dies, target opponent loses 1 life and you gain 1 life." Whenever Sephiroth attacks, you may sacrifice any number of other creatures
When you add in land-searching options like Town Greeter and the landcyclers, as well as four-mana ramp spells like Reach the Horizon, getting the mana together to cast Omega, Diamond Weapon or Coliseum Behemoth is a question of when, not if
While 4 might not be the only outcome if we want to determine the optimal number, its probably somewhere between 3 and 4
You need to spend it in combat, just like with Firebending