Sega released the promotional trailer for the game Closers Online, the animation is by the studio SILVER LINK with background music Cast Your Shell.
Therefore, the gaming company Naddic developed Closers Online and published it in South Korea in December 2014. Sega in turn released the game in Japan.
The game takes place in Seoul, after a dimensional portal opens and brings various monsters into this world. Players control a team of "Closers," psychic soldiers adept at fighting the monsters and closing the interdimensional doors.