We should put our bedrolls over our heads to soften the blows in case more rocks fall while we continue forward.
Temporarily gained +1 armour against falling objects.
There is another rock from above, but this one misses. And then a third, which also misses. Then it dwindles down into a rain of small stones, too small to do much harm to the party. The stones are hard, but they aren't heavy enough to break through your armour.
At this point, the crack bends, heading.. east? You'll call it east, it bent rightwards. The rain of small rocks also ends.. maybe there isn't as much clear space above you now? You can't tell, things are still strangely dark between the two walls.
At this point, Trence is last in line. Sessha of the million hitpoints is first. Willis is in the middle, protected position. And Trence is in the rear.
The next attack out of the darkness is beams of magic. There's a very weak blast of water, which fails to even crease Trence's dragon scales. This is followed up by a spark of lightning.. not a strong one, but stronger than the wet breeze. Still no damage, though. A third attack is made, this time of a small but more significant bolt of water. Finally, some damage is dealt, Trence taking 2 damage from the magic.
These came from behind and above the party, from right out of the darkness, with no visible source.