Boss Fight | Mission 9 - Vengeance Styx: Shards of Darkness Guide

The last task is killing the boss. Basically, it is predefined and it hinges on a single arcade element. You have to reach the ballista and fire it. Keep running to the left and avoid the opponent's attacks - stone throws and lethal beam. Time does not press you here, but you cannot save the game manually - there only are occasional autosaves.

Once you spot the light, the opponent will start trying to crush you after he spots you

You should be especially careful while avoiding the boss's vision - white light. As soon as you are spotted, you die automatically. Dash/roll between covers and use invisibility when necessary.

The last quartz - it's not too difficult to collect it

Alternatively, you can collect quartz. After Styx spots it, you will have to make it over to the other side of the crack, first. There, you will be able to jump down onto the rocks and reach quartz over handholds. Then, use the rope at the higher level to return. You will have to use invisibility to avoid being knocked down.