Saving the World in an Apocalypse-Style Text Game

Lin Xun unintentionally downloads a text game called "Book of Salvation".
Leveling up and taking adventures is just standard procedure.
Not only can he bring game items into reality, but he discovers that he can also bring game characters into the real world…
Although the game difficulty is hellish, luckily, Lin Xun has an unusual talent.
While other Apostles can only use one game character…
Lin Xun is hesitating over which one of the game characters he should use.
While other Apostles are still using weak human characters...
Lin Xun is already using powerful monster BOSS characters.
…
Then one day, when Lin Xun brings a terrifying BOSS into the real world...
"Would you believe me if I said I'm here to save the world?"