[@Pudding]
You're definitely right about Japanese culture believing that blood type impacts the personality, and - while it's not the only resource - [url=https://en.wikipedia.org/wiki/Blood_types_in_Japanese_culture]this[/url] gives an example. If this story is set in Japan, it might be a good idea to include that category simply because people around your characters are going to somewhat judge your characters based on it.

The category is also useful in role-plays that might include a hospital at some point, since blood transfusions or donations could occur. One other instance where it's useful is when there's vampires in a setting but these vampires actually work more in accordance with reality -- in real life, if you mix blood that doesn't match your own it can kill you, so fiction never seems to account for why a vampire won't get sick or die if they drink the blood of someone whose blood doesn't match their own.

Use as much as you'd like to, and no problem. Also, some of the more complex categories I left out include things like the character's marital status, residential status, how many languages the character can speak and what languages they are, and more complex classifications I won't go into unless someone asks me about them. I also left out anything that was unique to my project's setting.

I also left out the 'Astrological Sign' category, since I wasn't sure if you'd want to include it and the last time I sent this character sheet to someone it was for a role-play in a fictional setting that (presumably) wouldn't have used our astrological signs.