The Legendary Janitor
Most people don't choose reincarnation. Reincarnation finds their way to them. Perhaps they did something great in their life. Or maybe truck-sama wasn't looking where it was going. But without fail, those who reincarnate are destined for something great. A new life where everything changes for the better. But... Reincarnation isn't always the greatest thing. Sometimes you just draw the short end of the stick. Di Tou just happens to have drawn the shortest stick. Pulled out of his life randomly. Taken by a crazy old eccentric man not as a disciple, but as a body double?! And a janitor body double no less?! Grasping a system to find... It's a JANITOR SYSTEM!? Truly, how unlucky can one get?
[Bonus chapter] The Endless Hole
Somewhat unknowingly, Di Tou had come across one of the most useful aspects of Spiritual Sense, the ability to "see" and sense your surroundings in situations where the five main senses were obstructed.
As for why it wasn't mentioned in the jade…
Well, while it was one of the best usages for Spiritual Sense, it was also one that came almost exclusively with the territory of Nascent Soul.
After all, most people's Spiritual Senses are so weak that they're scared to let it outside of their body unless they're in a safe controlled environment where they feel safe.
As for wantonly letting out their Spiritual Sense to detect their surroundings… that might as well be asking for a concussion.
At most, in a dire situation, someone who could already use their Spiritual Sense would only send out a small strand to probe the space directly in front of them.