Probably a good idea to start with the wiki for Cao Cao - game version of course, not historical person, even if a lot of the game includes incidents from both history and Romance of the Three Kingdoms. At least the game wiki includes Oroch which is Cao Pi's canonpoint. Eesh it's big though, you can prooooooobably jump down to game 7/8/9 and then the Orochi stuff.

...whoops but yes there will also be a writeup, but that's good to have on hand in case the writeup I do isn't sufficient. I'll do my best without being too wordy!