Since we'll be leaning on Commander damage on a board after removal to kill, I have a few ways to make the Witch-King unblockable, including Shizo
Having the card draw to replace any of these dying is nice, but it comes in the form of Clue Tokens, slowing down how fast you can get the replacement cards
Once The Soul Stone is harnessed, harnessing it again has no additional benefit
Shirei, Shizos Caretaker Shirei, Shizo's Caretaker puts an interesting spin on reanimation commanders

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Thats 13 total damage that your opponents have to contend with