the Dalahästen train in the night, passing by some buildings, some blood on the circular saw but before the giant’s attackthe skeletons in one of the buildings it passes! So creepy.
That first time we fully see a troll, on the Dalahästen.
In the prologue you see the survivors erecting fences and learning to use guns, so there's clearly SOME threat but we have no idea what it is. When Tuuri and Lalli leave Keuruu on the ship, once they get out on the water the ship turns its lights off and shutters all the windows, and all passengers are instructed to be quiet. Again... some threat is implied, but still abstract. Then we gradually progress from seeing an electrocuted troll on a fence in the distance, to the giant on the train, to ceiling troll... and after that Minna basically introduced whatever Eldritch horrors she pleased haha. A slow, understated, but very real buildup in the story's tension.