Nightkin Ambusher can't be blocked as long as defending player has a rad counter
See rule 702.142, Boast. 702.142a: Boast is a keyword that adds additional rules to the activated ability that follows it
Even if you don't go down that route, I like Merieke Ri Berit much better as Mind Control on your commander since your opponent can't just kill this and get their card back
Some do, but many Korean sets feature exclusive artwork and unique designs not found in other versions
This thing is the ultimate upkeep breaker but even without it is a powerful, nasty, force that doubles your mana and draws a card every one of your turns
A strong zombie commander does one of three things: it makes tokens to go wide, it recurs creatures from the graveyard so your board never stays cleared, or it turns a pile of dying zombies into card advantage and life drain