Tokyo Ghoul √A, Owari no Seraph: Nagoya Kessen-hen Recommendations
Both series are about humans vs. "monster" (ghouls in Tokyo Ghoul, vampires in Owari no Seraph).
Both are very violent, bloody and kind of emotional/pshichological.
Both have the same number of episodes, 2 Seasons of 12 episodes and will probably have a 3rd Season in the future
In both anime the main charachter at the beggining is a normal boy that as a transformation (Kaneki as half-ghoul, Yuu as deamon weapon)
In both the humans are the weak ones so they use other things to fight (quinque in Tokyo Ghoul, deamon weapons in Owari no Seraph)
Both main charachters find a new "family" and have to safe their best friend