night wizard
Tabletop role-playing game by FarEast Amusement Research. The first edition was released in 2002, and it is currently on its third edition.
It takes place during the modern day in an alternate Earth similar to our own, named "Far-The-Earth," where a powerful barrier called Common Sense prevents most of humanity from realizing that magic and magical creatures exist. However, demon-like beings known as Emulators constantly invade past this barrier to prey on human prana (life energy), and magic-wielding humans known as Wizards must fight them.
An erotic PC game, Night Wizard Mahou Taisen, was released in 2004. Also received a 13-episode TV anime series produced by Hal Film Maker in 2007.
Characters from the anime: