Welcome to the Onmyou Taisenki guide at TV Tome.  Onmyou Taisenki is a digimon-like anime, has these things that look like digivices that are used by the heroes of the story.
All his life, Riku Tachibana has been raised by his grandfather. For some reason, the old man has always been fond of strange hand gestures, and they've rubbed off on Riku, who performs them almost subconsciously, to his classmates' great amusement. One day, however, it suddenly becomes clear to Riku what his grandfather has been surreptitiously teaching him. And the teachings could mean the difference between life and death for Riku.