You Made Me A Substitute Eunuch, Not A Regime Shaker

After transmigrating, Han Chen becomes a substitute eunuch in the palace and is immediately chosen by the Empress to guard her side. When the Empress is drugged, he saves her by accident, becoming her most trusted confidant. He discovers she is actually a woman disguised as a man. To help her secure the throne, he hides her identity, deals with palace intrigues, eliminates the Grand Secretary, suppresses the Duke of Yu's rebellion, and drives back the Northern Huan army. Through these feats, he is promoted to Champion Marquis and General of the Northern Frontier, eventually ruling the world alongside the Empress.