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?
The first part of the tribulation was straightforward. Mu Di Bai was a person, naturally he had his own friends and family as well as rivals and enemies. By going under Mu Di Bai's wings, all of those enemies would view him with hostility and perhaps even try to make moves on him in order to strike at Mu Di Bai indirectly.
All of these were tribulations that the current him couldn't face, much less him when he was at the Academy. After all, although he was no longer confident in what Mu Di Bai's cultivation level was, at the very least, he should be in the third set of cultivation. As someone in the third set, or of the Void Returning stage of cultivation or higher, naturally, his enemies would be of a similar stage. For people like these, much less Nascent Soul Stage cultivators, they would have Resonance Stage cultivators under their wings, and each one could easily kill a person like Di Tou with a flip of their palms.