-Rivaille is not Levi's actual name. The Japanese can't pronounce Levi's name so Rivaille was used.
-Levi is attributed with the literal title of "leader of the soldiers" (heishichō) (usually translated as "Captain") among the Survey Corps. However his comrades and subordinates usually call him by the shortened title of "Lance Corporal" (heichō). Which has lead to the wrong idea that he is actually a Lance Corporal, a really low rank.
-Mikasa and Levi share the same last name Ackerman, because Levi's mentor, Kenny Ackerman, had some sort of connection to Mikasa's father.
