Impossible to avoid Cloaked Figure, kills group outright.
Walkthrough says Optioinal fight--how to avoid it?

OK--got it done on Classic. The point is not to win or even survive, but protect Malady til she weaves her spell.

(On Explorer Cloaked figure jumped down and killed ecverybody; on Classic he didn't move.)

It can be done quite easy on every difficulty if you port Malady to the rear of ship, distance+higher ground.
This way she is out of reach for most attacks for at least 2 rounds and with blocking/slowing or buffing her you might even get through with Malady untouched.