What's Wrong with Being a Professional Janitor? I've Got an Iron Shirt Worth Billions

Lin Mo awakens an F-rank profession, [Sweeper Monk]. He thinks he's become a useless nobody, but unexpectedly awakens the strongest profession System. He can choose a technique from the start, and there's no level cap. Lin Mo immediately picks [Golden Bell Shield], and from that moment on, a monster is born. When calamities strike and the city teeters on the brink of danger, a golden light soars into the sky as countless layers of Golden Bell Shields unfold. The calamities are left dumbfounded.