Basically, The Dark is roughly only a third of Legends
We also add five new ally-color* decks and ten new enemy-color* options
To make a deck like this work, you need a way to deal damage to your own creatures when you want (Walking Ballista, Pyrohemia, Lightmine Field, Staff Of Nin, or even Prodigal Pyromancer cards), you need creatures that will trigger for being dealt damage, and you need a way to control the incoming damage so you arent losing creatures you dont want to (such as to a Skullcrack or similar effect, or an early Star Of Destruction)
4 Zirda, The Dawnwalker Discounted Cycling Zirda, the Dawnwalker is a solid companion (that's even banned in Legacy), but makes for a fantastic cycling commander
This might be a sign to run a couple more big spells
Its basically a repeatable discard effect since it triggers when dealing damage to opponents, and it has shadow