A former cheese maker's apprentice who got hooked on theater and the traveling life after seeing a performance of The Heterodyne Boys and the Mystery of the Cast Iron Glacier, Lars is part of Master Payne's Circus of Adventure; he plays Bill in the Heterodyne shows and with his partner Augie is one of the advance men for the circus, scouting out the terrain and making arrangements with authorities in the next town along the way.
He is a "great big chicken", and although he is not a spark, his unusual ability to sense danger is commented upon by other members of the troupe. He also experiences panic attacks after stressful situations, notably the small encounter with the Monster Horse Beastie (which, to be sure, would provoke panic in a far sturdier psyche than Lars'). On this particular occasion he takes a Calming Pie to the face, but it doesn't help much, to the mortification of the Chef, who's proud of his efforts in pastry science. Having Agatha with a great big monster-killing gun proves much more effective at calming him, reasonably enough. So does Ognian .. er.. a flying bridge-brick hitting him the back of the head, after the Circus's fight with the transformed citizens of Passholdt. (This incident also shows off the aforementioned danger-sense.)
Upon meeting Agatha, he is the one who recognizes her potential as an actress in the troupe's shows. Before long, although he has something of a ladies'-man reputation, he falls hard for her, enough to inspire him to go deep (literally) into the most dangerous place he has ever sensed and rescue her from Aaronev Wilhelm Sturmvoraus, and this all before . He dies saving her from a very, very angry Baron Klaus Wulfenbach and is deemed an honorary Jägermonster auxiliary by Maxim, who gives his hat for the burial.
Even though Lars and Agatha share kisses on stage, and he dropsto her about his interest, the flirtation mostly goes over the head of the less-worldly Agatha and she never acts on them until it is .
The version of Lars who appears in Agatha H. and the Clockwork Princess is pretty much the same as the one in the comic, except that he and Agatha's off-stage romantic relationship progresses a little farther before the dramatic events in Sturmhalten cut things short.