Erik was from a working-class Winden family, the son of Jürgen and Ulla Obendorf. He went missing on the evening of October 22, 2019 when he was 15. He had run away from home before, but had never being gone more than a few days, perhaps sleeping in the basement or wherever, per his father.
Erik and Jürgen were selling drugs at the high school. Erik kept a stash of drugs along with a mobile phone in an old armchair at the entrance to Winden Caves, and another stash at his father's junkyard, which Ulrich Nielsen finds and confronts Jürgen about. Erik had been saving money to buy a scooter.
They encounter each other, however, and Bartosz takes the drugs from her. Just then, they all hear the noises coming from the cave, birds falling from the sky, and branches breaking, and their flashlights start flickering, sending everyone to scatter in a panic. In the confusion, Mikkel Nielsen disappears.
Bartosz unsuccessfully attempts to unlock his mobile phone. Later, however, he receives a call on it, from someone he assumes must be Erik's supplier. The man on the line, Noah, seems to know who Bartosz is, and arranges to meet up with him.Erik is next seen in a mysterious room decorated with cyan wallpaper with cartoon animals, and full of children's toys, bunk beds, a television playing 1980s music videos, and a strange chair. On November 5th, 1986, he is gagged and strapped down in the chair by a hooded figure, later revealed to be Helge Doppler.
The chair is a primitive time travel device, and it transports Erik to 1953, but kills him in the process. Helge travels to 1953 through the cave to take Erik corpse and place it near the construction site for the nuclear plant.  He later does the same with Yasin Friese's corpse on November 9th. Both corpses are discovered on November 10th, 1953. 
- Bartosz assumes it is Erik's supplier calling Erik's phone because he does not know that Erik and Jürgen are in business together. Likely, Jürgen obtains the drugs and Erik distributes them.
- Erik and Mads may have been in captivity in the bunker during the same time:
- Mads went missing on October 9, 1986
- Erik went missing on October 22, 2019, but taken to 1986 by Helge
- Mads dies in chair time travel the night of November 4th from 1986 to 2019
- Erik dies in the chair time traveling on November 5th from 1986 to 1953
- He would have spent almost 2 weeks, between October 23rd and November 4th 1986, in the bunker. It is not clear if any others accompanied him.
- No one saw Mads in the bunker, even though he went missing before Erik.