I long forgotten the story and had dropped the thing within 30 chapters... But here goes, MC is a peasant centurion and a candidate for promotion to knighthood by his commander and his competitors are all nobility, one of them is even a count's son. Compared to them, MC has wisdom ie play dead in the army and lived to tell the tale plus learning shitty cultivation techniques and musters only a pearl size aura in his dantian. I dropped it after awhile because it is very very slow. The person who intro-ed me this work says that it is engaging because how the MC uses his smarts instead of his fists (cuz god knows it doesn't exist) and I am perpetually creeped out by him saying that his sister is sexy.