Colorless back faces, such as lands, do not
Subira is a great way to make sure that Mrton can attack more than once and Siege-Gang Commander gives you 4 bodies
Counter target creature spell
Some competitive deck builds run with as few as 4 energy cards, but theme decks can have as many as 20 or 30
Mostly, this gives you a Zombie at the end of your turn if you lost 2 or more life, and losing life on your own turn isnt something that will just happen -- youll have to create situations to make that part work, and even though Black is always capable of doing that in Limited, it is highly unlikely you get a critical mass of those cards going that allows you to consistently make a Zombie, and you probably need to get at least two out of this for it to feel worth it
Sufficient natural or even added artificial light/flash is encouraged so long as it does not intentionally or unintentionally obscure or hide damage on a card