I would probably assume he's just really into Romance of the Three Kingdoms or other historical dramas where the 司馬 surname is common. Or that his real name is Zimmerman.
I've read that a number of Chinese with the surname 欧阳 [Ouyang] logically chose the English surname O'Young, confusing a lot of people who were led by the name to expect someone more Irish.
I've read that a number of Chinese with the surname 欧阳 [Ouyang] logically chose the English surname O'Young, confusing a lot of people who were led by the name to expect someone more Irish.