I not only expect to see tons of these in sideboards but also creature strategies to be built around this powerful artifact
It saw a lot of play in its Standard as a way to take extra turns by paying the 7-mana cleave cost, but also allowed you to combo off early via the pure red version
While this is game plan number one, a well-timed Metamorphosis FanaticMetamorphosis Fanatic/Phyrexian DelverPhyrexian Delver will bring beaters into play after you've Unshakable TailUnshakable Tail looped as many creatures to the yard will keep the pressure up
Library of Leng is a fantastic, low-cost utility piece that allows you to put discarded cards back on top of your library instead of into the graveyard
Functionally, what this effect says is that if you can attack with The Lord Master of Hell, and you have 40 or more cards in your graveyard that are neither creatures nor lands, you win the game
Crucial Tip: Semi-rigid holders: Thinner and more flexible, these are the industry standard for submitting cards for professional grading