That is less of an issue if you have some power enter the battlefield effects, or have spare energy lying around you can easily pay for the mana cost for a turn or two.
If there's a cost associated with blocking Anzrag, the defending player isn't forced to pay that cost, so it doesn't have to be blocked in that case either
In case your commander isnt on the battlefield yet, you have Fate Unraveler and Underworld Dreams to keep pressuring whenever your opponents draw cards
I found it to be the way that I most enjoyed playing
Crew 2 If X is a very large number, you may be required to roll more dice than you physically can in a reasonable time frame
A deck that focuses on graveyard recursion and reanimation would greatly benefit from Rise of the Dark Realms, as it allows for a powerful board presence and can swing the game in your favor