@Seth @Fleet Admiral Lee Hung
Also, the Chu should have - amongst the ones we know for now at least - the likes of Renpa (who is 100% fighting for them), Shouheikun (who'll also fight for them) and Karin. We know how hyped these people are, right? If Kouen is set up to be the "main", #1 antagonist there, it's yet
another clue to how outrageously powerful Hara will have him be.
As much as Hara generally follows historical trajectories/events, he's super fine in also having things different in other aspects. In his manga, just to cite a single random example, Renpa and Ouki are equals, whereas in RL Renpa was clearly the greater general. Hara has also blatantly set up Shin to be greatest GG of all times (this was, again, never the case in RL)... and guess who was an immense enemy to Shin historically? Kouen.
In the manga were Kouen will be set up to be this
extremely important foe to him (again, the man who Hara will make the GG ever), his in- manga portrayal, his future role in general...it's clear that Kouen will be something absolutely terrifying. If it turns out that Kouen is a
stronger general than folks like Ouki/Renpa (with the gaps not being big ofc, they are all at that top level), I wouldn't be surprised in the slightest.