If you manage to satisfy all four in the same turn, he transforms into an upgraded version that repeatedly generates life, cards, counters, and damage every upkeep while also discounting your spells
If you don't get your nut draw where you do something insurmountable on turn two, you're going to have to improvise until you can
Reshiram ex 174/086 has taken the top spot here, priced at $347.76, basically mirroring Zekroms dominance
Likewise, Druddigon is a wall designed to buy you time to set up strategies on the bench, but if you don't have anything to make use of, it's a pointless delaying tactic
You no longer need to pack in cards that can handle Nadu, so you can afford to try and counter some of the other top decks in Modern
You can wait for a more advantageous pairing if you like