Heimertz was selected to guard the Balm spring in Nod's Limbs after his predecessor died, forcing him to stay in Nod's Limbs and leave his family and his then girlfriend, Madame Dahlia.
He is abnormally strong and has the uncanny ability to appear as if out of nowhere. He is the only person who truly unsettles Edgar and Ellen. Despite that, Heimertz was the only person looking out for them ever since the twins' parents left. Even after the twins got him imprisoned by his circus family, Heimertz risked his own life to save them after they were trapped in a cave-in caused by Stephanie Knightleigh.
Through the years, Heimertz became friends with Pet, whom Heimertz protected from the twins whenever they tortured it, and has also protected the twins after their parents' departure.
Heimertz has black hair, small black eyes and tanned skin. He usually wears stained blue coveralls, a blue shirt with rolled up sleeves, a brown hat, brown gloves and brown hiking boots. Tall and imposing, he moves seemingly without flexing his joints, always smiling a blank, toothy grin. On the single occasion he spoke it was compared to a rumbling boulder. ("High Wire")
Heimertz's most prominent character trait is being a quirky man with many eccentric qualities; He doesn't talk unless it's absolutely necessary and his idea of caretaking of the mansion's grounds is to do pointless and/or dangerous things like peeling bark from trees or digging holes on the ground.
He is also very patient as seen when Edgar and Ellen chained him up and tried to torture him, he was unfazed by it until Edgar threatened to destroy his accordion, although Heimertz simply took the accordion and disappeared.
Though ordinarily calm and quiet, Heimertz shows an aggressive and dangerous aspect of his personality whenever he is crossed, as toward his family for questioning his loyalty to them when he tried to use Balm to cure Pet. However, he is very loyal to his friends and family and will protect and help them no matter what.