The only downside for Zareth is if you want to use its second ability, you have to somehow get it into your hand, which can be done with ninjutsu cards like Prosperous Thief, trading them back and forth from your hand
The five basic land types produce white, blue, black, red, and green mana, while hundreds of nonbasic lands offer special abilities or multiple colors
Incidentally, equipping this to said costly Commander can usually ensure two or even one-shot knockouts with Commander Damage, which is pretty spicy indeed
you can play the awesome Thragtusk instead
For example, if youre playing a R/G mirror match, and you need some way of pushing your guys through for damage, you might want to bring in Nightbird's Clutches or Cobbled Wings
The card really does do a lot, and if decks like Mono-Black Devotion and Mono-Red Aggro werent in the format, Id play all four maindeck