Update and hope it helps those trying too:

I didn't manage to "solo" it but it was quite easy with another person.
he grabs warlocks and starts nuking healers first and then king.
I got control ok king (to move when needed or strike too);
both healers (spam heal on warlock doing his job and later on king to finish it);
and another one grabing whatever piece just to mess around with their king (started with grunt, finished with wolf).

Got it done and Prince was easier than chess...