User blog comment:Hitsuji Mamoru/FGO-style Servant Creation Room/@comment-4802891-20170128130847/@comment-30314236-20170128143815

I understand what you mean. Lore-wise, he should be someone only effective against vampires (Bloodsucker skill), but there aren't so much in the game, so he is very situational.

Yes, it doesn't make sense for him being anti-Berserker (but it would be funny Helsing VS Fran). You can extend its functionality adding undead, demon and beast trait. It would not be very good against a lot of Servants (Jaguar Man, Tamamo Cat, Shuten and Ibaraki + those with Bloodsucker skill), but enemies like soul eaters and quimeras, who are really abundant in all the game. Vampires can be considered undead, beast and demons, after all.