Took me forever but got a no hit run. I wish I could go back to show the configuration I used. Used Big bones + nurses and immunity spell book to take down the King.
18 days ago(+1)
I have done no-hit runs 10 times or even more.
It's possible to defeat the King with 1 alpha-unit with lots of supports, like nurses, and assassins. But as for me, Bard-Rocker-Something respawnable is much better.
That's the last run start of the boss fight: