Arno starts in cover and that is a good thing. Germain's Relic is very powerful. It allows him to launch lightning bolts from it as a beam. It can also call lightning down in a particular location. Germain will only do this if Arno stands in one location for an extended period of time.. He will have quite a bit to say to Arno. While this does
Throughout this encounter, you are going to want Eagle Vision active. Only approach using Stealth Navigation and from behind. If you are having trouble, this is the time to use some Cherry Bombs to turn his attention away from your approach. Move in and try to stab Germain. He will disappear in a burst of lighting. Time to find Germain again.