INSIDE DIMENSIONS: 3.11" x 2.20" x 4.41"
Set Inpachi, then after your opponent fails to destroy it as a result of battle, change it Attack Position on your next turn, then equip it with Horn of the Unicorn for a combo attack
Sigarda, Herons Grace making your board harder to deal with and the sparsity of boardwipes present in the BC environment is going to make most of the creatures and effects stay on board for a while - additional board protection and creature tutors would likely have to be limited to keep the deck fair for the BC environment
So, perhaps we will need answers that are both flexible and hit black creatures
These forces of evil won't just be working in the shadows
In reality, though, throwing down your credit card at this point is no better than buying the latest hot Standard mythic right after it crushes a Pro Tour Top 8