Once per each turn when you activate ninjutsu, you can look at the top three cards of your deck, take one, and put the other two at the bottom
In decks where you can amplify this damage like Torbran, Thane of Red Fell, I can see this pulling some weight, but I wouldn't run it aside unless you're really committed to Burn + Spellslinging
Duress can also remove opposing Lightning Bolts and removal, and that comes in very handy against pretty much every matchup, except maybe hatebears
Yes, Lord of the Undead is a zombie , which has been clarified on most recent printings
I would only buy these playtest cards from trusted sources as they have the potential to be very easily faked
Given how its limited to Arena, I have a hard time quantifying it against paper cards