Shikong Zhi Xi
English title: Rift
Japanese title: 时空之隙
Type: ONA
Episodes: 13
Source: Game
Genres: Action
Studios: B.CMAY PICTURES
Producers: bilibili
Duration: 21 min per ep
Rating: PG-13 - Teens 13 or older

Unstable energies of the present world and an alternate realm has ripped open a rift of time and space. It is the only passage where monsters from the alternate realm can enter the world. To stop the invading monsters, a group of chosen people step forward to fight and protect the world at the rift.

(Source: bilibili)