Mirai Nikki, Shiki Recommendations
Although not the same, there are striking structural similarities. Mirai Nikki has a protagonist who recieves an empowering item that puts him at great risk and requires him to forge alliances and take arms against others within a similarly affected group, with his survival primarily dependent on knowing who to trust and when to trust them. Shiki is about a group of protagonists, some of whom become supernaturally afflicted, whose survival is dependent on knowing who to trust as the death toll climbs. Not the same, but similar.