I'm Really Invincible

Zhao Bufan in the real world traveled through time, He came to a fantasy world full of immortal cultivators. Before time travel, he was a submissive office worker. After traveling through time, he got a system, and his system was different from other people's systems! Other people's systems were all about killing monsters and upgrading, but his system simply let him sleep for a hundred years. After sleeping for a hundred years, Zhao Bufan is now invincible!