Blood+, Kyoukai no Kanata Recommendations
Both girls use blood to kill their "monsters".
Both have somewhat of a love interest.
Both are really good and full of action.
Both animes feature supernatural, school girls who use their blood to fight demon-like enemies as their main characters. Both are action oriented with a slight hint at romance. Blood+ has a more serious tone about it, whereas Kyoukai no Kanata has a lot more jokes. If you want something a little longer and little more serious, check out Blood+. If you want something quick and fun, watch Kyoukai no Kanata.
The main female protagonist of both series both series uses blood to enhance the abilities of their sword,though Saaya(the female protagonist of Blood +) uses an actual Katana.
Both have to deal with killing supernatural monsters.
The main male protagonist of both series are somewhat immortal.
The action of both series are somewhat similar.