Why do game manuals sometimes give a character's blood group along with the expected name, height and age? Have a watch for the significance of blood types in Japanese games and find out if you're a compatible donor for the cast of Resident Evil, Final Fantasy and Street Fighter - at last.
Some people in Japan believe your ABO blood type governs your personality. The concept was born in the early 20th century and popularised in the 1970s by a book by journalist Masahiko Nomi. He called the idea "blood type humanics", which sounds sciencey but is not very.
Whether the audience takes the idea seriously or not, its familiarity in Japanese culture makes a character's blood type a decent shorthand for suggesting his or her personality, which is a good reason for listing blood type alongside other vital statistics. As a bonus, you're all set if you ever need to give Albert Wesker an emergency transfusion.
For more adventures in pseudoscience from Outside Xbox, watch what Alien: Isolation does to your heart (and face).