The title aims to train memory and concentration.
http://www.nintendoworldreport.com/news/29353
Oni Training (or "Demon Training"), the newest title in the Brain Age series, was revealed by Nintendo President Satoru Iwata during Nintendo Direct.
The game is a spin-off of Dr. Ryuta Kawashima's Brain Age for 3DS, focusing on training the players memory and concentration. It features a demon version of Kawashima. Iwata said that the game attempts to give players a serious challenge while avoiding frustration.
Nintendo plans on revealing the final title of Oni Training, as well as other details, at a later date. It is currently set for a summer release.