Lighting

Brad, since there is a light source illuminating part of the map how much of the non-illuminated area can be considered "Dim Light"?

Dim Light
This category includes the light provided by a candle or another dim light source, moonlight, indirect illumination (such as in a cave interior whose entrance is nearby or in a subterranean passageway that has narrow shafts extending to the surface), and the light cast by things such as phosphorescent fungi. Characters who have normal vision can’t see well in dim light: Creatures in the area have concealment. Characters who have low-light vision or darkvision see normally in dim light.

Since there is some light in the room that Blade was in I think he would have been considered to be in Dim Light and the guardian would have Concealment instead of Total Concealment.

He hit and killed it so it doesn't matter for that case, but may come up again since undead love the darkness...

Dim Light
This category includes the light provided by a candle or another dim light source, moonlight, indirect illumination (such as in a cave interior whose entrance is nearby or in a subterranean passageway that has narrow shafts extending to the surface), and the light cast by things such as phosphorescent fungi. Characters who have normal vision can’t see well in dim light: Creatures in the area have concealment. Characters who have low-light vision or darkvision see normally in dim light.

Darkness
Darkness prevails outside on a moonless night or in rooms with no light sources. Characters who have normal vision or low-light vision can’t see creatures or objects in darkness. Characters who have darkvision can see without penalty.