Solid-Stark on 26 June 2014
No, he is not hard to find so as long as you look into all rooms/corners of particular areas. I won't say which because I'm not sure if you count that as spoiling. The NPC is found in multiple areas and is needed to be found in all areas.
You will see Vendrick. Hard to miss him. His fight does require information which I won't say because you may consider it a spoiler. Good luck.
e=mc^2
Gaming on: PS4 Pro, Switch, SNES Mini, Wii U, PC (i5-7400, GTX 1060)
