In Japanese culture it is believed that one's blood type can tell much about them. Squaresoft specifically made Zell a type B, so what kind of traits did they want Zell to portray?

Information on blood types gathered here.

 
Type B blood types are defined as hunters. Contrary to Farmer types these people are non-conventional, and care little for other people’s opinions. This makes them thick-skinned. This doesn’t mean they are uncaring. Indeed, they are extremely passionate about things dear to them. The negative side to their personality is that they can seem shallow to other people, and lazy, because they might not do what other people request. If they don’t get their own way they can seem impatient.