OK, remember in your next fanfiction that you write that Mikasa Ackerman (blood type AB) from Attack on Titan ABSOLUTELY CANNOT give a blood transfusion to Tuzki the rabbit (blood type A) but it's safe for Tuzki to give a blood transfusion to Mikasa Ackerman (rabbit and human blood group differences aside). Wait no, they could get screwed over by the rhesus factor if it turns out they're A+ and AB-...