I played all the dw games and wo games except dw3xl and dw8xl.
1. Xiahou Dun. Most favourite character since dw2, atlhough the dw3 english voice acting was absolutely terrible and the dw6 design wasn't great either. I still can't decide whether I prefer english va or the original one as I believe Kirk does amazing job in showing Dun's short temper, much better than Kazuya Nakai imo. However the japanese va is just plain badass.
2. Jia Xu. You just have to like this guy. The VA is absolutely great, the personality is great. He's smart and he knows it but shows no signs of arrogance or overconfidence unlike the likes of Zhuge Liang. I really don't like his DW7/8 moveset except for musou but his personality makes me enjoy controlling him on the battllefield. Gotta love his humour as well.
3. Zhong Hui. As stated in the previous post this is Zhang He done right. I especially like him complaining to Sima Yi after the relevant stage in dw8.
4. Cao Cao. As stated by Guo Jia in DW8 cut scene 'don't worry, he knows what he is doing'. Being a Weist I never viewed Mengde as antihero regardless of how hard KOEI tried to convince me in early games. Douglas Rye does a great job in voice acting. I really don't like the japanese va though. Cao Cao's final scene in dw7 was quite emotional for me even though I rarely get immersed in video games.
5. Guo Jia probably...I always wanted Guo Jia playable especially after DT2, but I really was disappointed with his joke weapon. His personality also didn't impress me as I expected him to be more like Jia Xu. It was only after the intro in the Xia Pi stage that I start to like him.