Chris Sanders (unknown episodes)
Achim Decker / ... (7 episodes, 2001-2005)
Dr. Martin Stein / ... (235 episodes, 2005-2011)
Rainer Jonas / ... (2 episodes, 2002-2010)
Rolf Dressler / ... (2 episodes, 2003-2006)
Joost Fuhrmann / ... (2 episodes, 2003-2004)
Philip Glees 15 episodes, 2015-2016