If you play something like Elves, Goblins, Humans, or Merfolk, you can fill your deck with 30 creatures of the right type and never worry about your mana curve because these creatures exist at all reasonable points in the curve, but if you ever play 30 Giants in a deck, then the average converted mana cost will be five and you will lose most games without ever casting a spell
We ended up making an enchantment that enters and gives you two 2/2 black Zombie creature tokens and then lets you spend mana to turn dead creature cards from any graveyard into Zombies
Due to not wanting to attack with 5/5 Gideon if you are behind on the board, you tend to just churn out 2/2s and as such you never work up a buffer of loyalty
Activating that rat-doubling ability requires a sacrifice, unlike Krenko, which works well for a mono-black death strategy and pairs nicely with the rats that are good sac fodder or sac and death payoffs
The ward cost is harsh and amass for every opponent's spell really adds up