It was thought breaking this damages one's soul; since vampires have no soul, they can't be seen in one
[DOC] [TLE] Hellsing Ultimate - Wikiquote [PAR] 1 Alucard; 2 Seras Victoria; 3 Sir Integra Fairbrook Wingates Hellsing ... "Now, 
Luke Valentine, it's time to educate you on how a real vampire does battle!