There's one blue sphere magic light outside the crown room in the ruined tower, it has a dialogue box that explains how those lamps work, i.e. hit them with any magical damage and they light up. That's great, the only problem is, there are several of those blue spheres in the crown room itself, and I couldn't target any one of them. Lighting those up to provide light in that room would have been extremely advantageous in the combat, but I tried to target them with my wizard's Firebolt cantrip, and they were not clickable. It appeared as though all those blue sphere lights were just dungeon dressing, and weren't actually created to be interact-able objects.
Blue Sphere Magic Lights not lightable
2 years ago