Hiro's parents and Aunt Cass.
In one scene, Hiro is talking to his Aunt and there's a picture of what I assume to be a young Tadashi (Looks like Hiro with short hair but he said he was three when they died) standing with two adults who look suspiciously Asian...
If both Hiro's mother and father were of oriental decent, then how the heck is Cass related to anyone, when she looks obviously Caucasian?