I Was Told to Pose as the Crown Prince, So How Did I Become an Emperor for the Ages?

A top spy transmigrates into Wei Yuan and lands in the Great Wei dynasty, where he becomes the stand-in for a useless crown prince.

To help Wei Yuan deal with the emperor, the crown prince even offers his own crown princess as a reward:

"Go deal with him. When the time comes, the crown princess will keep you company!"

Wei Yuan sneered. "Don't worry. I'll take good care of the crown princess!"

At first, Wei Yuan only wanted to survive, while Emperor Wei merely intended to use him as a whetstone for the Fourth Prince.

But things took an increasingly unexpected turn.

The Fourth Prince: "Father, is the crown prince really just a whetstone? My blade is about to snap from all that sharpening!"

Emperor Wei: "Crown prince, are your eight hundred thousand troops surrounding the capital really a gift for me?"

The crown princess looked at him suspiciously. "Wei Yuan, are you really just a hoodlum? The emperor's shadow guards' chief is your lackey, Prince Yong's spies are your women, and even the daughter of the Marquis of Jing'an..."

Wei Yuan shrugged. The grassland princess wants to marry me and bring the entire grassland as her dowry. Should I say yes, or should I refuse?