Courtesy name Gongjin. Zhou Yu is the fifth member of the Eight Enigma, genius military advisors handpicked by renowned veteran strategist Sima Hui 'Shujing' from his students. Of all the Enigma to have made an appearance, Zhou Yu's goal strays the furthest from their common ideal: rather than striving to bring peace to the land, he pledges loyalty to his sworn brother, Sun Ce, and dedicates his genius to the resurrection of the fallen Sun clan, which implies his intentions to found the future Wu kingdom independent of Imperial Han. For this, he's greatly disliked by the Seventh Enigma Zhuge Liang, who likens him to Sima Yi, another man of staggering brilliance but without noble ambitions (coincidentially, they also look nearly identical).
Zhou Yu's strength lies in troop deploying and counter-espionage, the later of which was the basis for his ingenious scheme to turn Yuan Shu's men against each other, tremendously diminishing Yuan Shu's force. Thanks to this, Sun Ce was able to escape safely to the Eastern region and fight to regain it, laying the foundation for the Wu kingdom.