Tronte Nielsen is the father of Ulrich and Mads Nielsen, and one of the few characters who appears at his natural age in all three eras.
Tronte moved to Winden in 1953 with his mother, Agnes. They rent a room in Doris Tiedemann's house, where he first meets her daughter, Claudia. Doris briefly asks Agnes about Tronte's father, to which she replies he had died before adding that he was a reverend that didn't believe in the divine, leading to speculation he might be, in fact, Noah.
Claudia takes him on a tour of the forest, rejecting the company of Helge Doppler, who sends her dog Gretchen into the Winden Caves out of spite. Later, when alone, Tronte pulls up his sleeve to reveal apparent cigarette burns made on his arms, although the cause is not revealed.
By 1986, Tronte was working as a local journalist, and unhappily married to Jana Nielsen. He carries on an affair with Claudia, who has been made director of the Winden Nuclear Power Plant. The disappearance of his son Mads shatters the family; Jana becomes distraught and withdrawn, and Ulrich becomes rebellious. Ulrich later discovers that Jana lied to the police when she stated that Tronte was at him with them on the night of Mads' disappearance. Jana assumes that Tronte was with his lover, Claudia.
In 2019, Tronte is called out to the cabin on the same night as Mikkel Nielsen's disappearance, where Peter Doppler has discovered the corpse of the missing Mads. Claudia arrives and has them move Mads' body into the forest where it will be later found by the Winden Police. Peter and Tronte are following Claudia's instructions, as noted when Tronte states that Claudia's predictions have come true thus far.