ARISA
Complete | andou natsumi | 2009 released
2017-06-04 02:00 marked
Not exactly horror but it has many plot twists and kinda similar to "Ousama Game". Features less gore and more suspense. The art style is a MAJOR PLUS, I like how the mangaka used cute, shoujo drawings and turned them into one creepy, mystery story.
Ou-sama Game - Shuukyoku