This card isn't 'win the game' but it certainly is powerful and annoying, because it is fairly cheap (although the lack of colorless mana cost does make it land restrictive), protects itself just enough to be annoying, and has a solid body with a good ETB effect
Adding green gives you some powerful flexibility options, and Sidisi, Brood Tyrant makes more zombies for free
Just remember to loosen your standards as your number of cards gets lower
At six mana (three colorless, one each blue, black, and red), he's a little more expensive than other Commanders you're likely to encounter, but he brings excellent value and staying power to your battlefield
First to three points wins the whole enchilada
In lieu of indestructible, these creatures return themselves to the library whenever they die or are exiled from the battlefield