Both series deal with relations between human and non-human characters (vampires and ghouls) who live and work side-by-side. They both feature lots of violent, bloody battles with supernatural elements.
JaserHyakuya asksDoes Guren's bond with Noya make him stronger than The Absolute Sword, Zekken? "It pains me to see someone so pitifully weak," Guren said with a laugh, drawing his sword. Shadows escaped from the sheathe.
Yuuik just smiled. This guy had fake power from a demon. She had... Mother's Rosario!