The only thing this could develop into something that does not feel like a fuck up by the author would be kyokai suddenly waking her Percy side
"Shin, I need you to make my babies"
When i reread this manga in the future, I simply will ignore any chapters with houken on them. Ouki was killed by an arrow. Duke Hyou sacrificed himself against masses of enemy troops. And that is it.
At least we can forget about him now
Some mangas/manwhas are awesome from the start. Others "have potential". Solo leveling was one of those. And as a lot of times happens, the author has not been able to capitalize that potential. This arc is a major letdown