If it does trigger, if you don't control four or more creatures as it tries to resolve, it does nothing
In Golgari or Jund shells this is quite tasty
The primary commander is Sevinne, the Chronoclasm, and the secondary commanders are Elsha of the Infinite and Pramikon, Sky Rampart
If not played mindfully, this commander will enable other players who deliberately tuned down their commander choice to not have Trample, like Tuya Bearclaw or Alana and Helena, Partners to have a way faster or easier game
(As this Saga enters and after your draw step, add a lore counter Sacrifice after III.)
Its a powerful card, anyway, and it sure does give us a boatload of sacrifice fodder