Time to get to work

Zankas can feel his mind is returning as he looses sight of the fresco.

TDK laughs Where are the others, they will miss all of the fun!

"Trapped downstairs. Some form of magic seems to bind them to the room." The elf points in the direction of the opened door.
Rervenn waits for the sword to emerge once more and readies her bow.

Coughing Melang and Zankas get out of the smoke, free of the enthraling fresco. There are some stairs going up.At the end of each bridge, that spans the entrance foyer, are closed adamantine doors.

TDK quietly say: It see YOU through the bridge! Get out of here! he steps 5 feet south giving Rervenn way (if that's the direct she would like to move) and draws his flail (free action, hoping that sword does not have flyby feature). He moves moonbeam 40 feet down (it is 40 feet tall and I need it to be right below us) and as close to Rervenn as he can, given he can move it up to 60 feet).

When TDK realise that sword is gone he calls griffon back and flies down to help magically Trapped Zankas and Melang, but as far as I understand he discover that they managed to free themselves.
Ah here you are. Are you OK? Anyone feels smart enough to check out a book and an artefact over there? And we would benefit of your light of course.
I believe we could go up using stairs and find ourselves on the upper floor. TDK will not go over the rope ladder, he is too old and heavy for that.

TDK start running toward the empty segment of the bridge as if crazy, but at the last moment some magic sparks in his boots and he jumps over:
My long jump is 13x3=39 feet if I move at least 10 feet on foot immediately before the jump.
TDK lands heavily in his full plate, but boots magically slow him down. He turns around: Actually I could share boots that could allow one of you to spiderwalk but you need to attune to it he explains. Though having a short rest may not be a bad idea for Rervenn got quite beaten.

You all gather to catch your breath and examine the found artefacts. You find that the book is a book of shadows, a warlocks tome. In it there are instructions on how to call fourth imps from the land of fire and shadows. Its clear that someone made those 4 summoning circles on the bridge (blue square). Could it have been the fifth imp?
Its also clear that the previous group had taken a rest, just as you now do, on the other side of the bridge. An explors backpack have been left behind.
Rervenn suggests that the imp and the sword properly belonged to one of the raven queens warlocks. If his book, sword and imp are left behind then you properly find his body somewhere further onwards. At the end of each bridge, that spans the entrance foyer, are closed adamantine doors.

Fiends were summoned on the middle bridge, it is obvious we must go through middle doors The Dark Knight suggest to start with middle doors. You may find that he seems to be more concerned with the fiends and happy to kill them than the mission itself.

Whoever summoned the imps may have trapped the doors, I suggest caution And TDK describe that he would use mage hand to open the doors from a distance.

Zankas looks warily at the bridge. Whether or not the middle doors are obvious, only time will tell. But it would seem any direction is better than none, yes? Let's be careful and not rush, I agree. I have some magics that can help in preparation for conflict, so if we proceed level-headed, we may gain some advantage. he says with a quirked lip. I will certainly follow your well-armored lead however. he finishes, with a nod to The Dark Knight.