Whose death do you think was the most unfair?

I disagree. Laslo was only helping Isabella-Biare. And Biare herself caused much more trouble. It's more appropriate to feel sorry for Laslo or Markel than for Biare.

Laslo forced Frida to join the rebellion and is therefore indirectly responsible for Godrick's death. And Markel almost destroyed the entire Erathia and the Academy.