Sarkhan, Fireblood is that turn 2-3 ramp card you want to be casting in Dragon Tribal, basically a superior Urza's Incubator since for most turns you'll only be casting one Dragon per turn and Sarkhan also mana-fixes and also can rummage for you if you don't have a Dragon spell to cast
For Commander, the number of lands you want to run in your mono-white decks can vary a lot based on how low your curve is and how many mana rocks and other ramp pieces youre running
As a top end finisher, its going to be good at sniping away pesky token blockers that get in the way of your draconic domination
If youve been waiting to pick up cards like Akromas Will , Black Market Connections , and Exquisite Blood , this might be your best chance to get them at a reasonable price for the foreseeable future
While control decks typically leave a lot of mana on the board outside their own turn, this will raise alarm bells for your opponent, who may look to counter if possible
Undying is creature-based recursion mechanic that is essentially the mirror of persist