What was the point of Marco coming along

body count

Maybe that's why they invited "Claire" (who didn't show up due to some business deal)?

They needed more characters and something to add more to plot, since you know... there was none.

I thought there would be more back and forth of characters turning against each other - Marco was the first to be bewitched by Silka.....so a third person would be a useful device for "divide and conquer". But this possibility wasn't explored to its full potential, I think.