Here are the characters I personally found most detestable, starting with the most detestable.
1. Zhou Zhiruo
2. Miejue
3. Chen Youliang
4. Zhu Jiuzhen
5. Zhu Changling/Wu Lie
7. He Taichong/Ban Shuxian
9. Zhu Yuanzhang
10. Ding Minjun
For some reason, I don't hate Cheng Kun. The guy was clearly an evil mastermind, and yet somehow he always manages to make himself look weak every time he appears, that I can't help but dismiss him as more of a joke.