I don't know much about this anime so I have little to go on.
Main parts of the anime:
main character is a girl who traveled to a magic city to learn to be a healer in the academy. She gains a male friend with black hair and uses a sword. The headmaster of the academy is an old guy who is draining people that are imprisoned underground below the academy.
Other information:
I believe the anime came out sometime in 2015.
The headmasters eye turned red. (Don t think he was human but he looked it)
I don t know the girls hair colour or eye colour.
EDIT: I also believe that to graduate from the academy they have to duel another person and usually the winner graduates (She -the MC- might of lost her duel but then graduated for the events of the prison)