That might not even be Makou though, on the third page he say thinks "Not good, I'm still holding Makou's glaive"
The one who thought that was Makou's aide, who was holding Makou's glaive for Makou because there really was no direct need for Makou to have his glaive with him because they were destroying Kisui.
Ousen sort of had to have the rug pulled out from under him simply because he had "too much momentum going for him" seeing as he orchestrated everything up until this point. So there had to be something that would have levelled the playing field somewhat.
But still, this surprise assassin sneak attack somehow feels hamfisted. It's silly to think someone with as much hype as Makou (being Ousen's right hand man) falling to such a scheme this early in the battle.
Akou better not get killed like this. Ouhon, Mouten and Shin are gonna have to step up.
Also, I've been reading up on some Zhao on the wiki and it seems a few characters of noticeable reputation are still missing from this "battle for survival" for Zhao, most noticeably Gaku Jou, a Great General who is reputed to have been the second greatest general in Zhao when Renpa was present and whose skills secretly surpass those of Renpa himself. I wonder if he'll also show up somewhere in this war.