Reminder (again): this arc started because Glenda (seen here in Half's flashback), who had about four appearances before now, was killed by some dude everybody forgot (well, Mirabelle did it, but under his orders) and this dude is also dead now, he lasted like 10 chapters or maybe less I forgot.
Nobody has ever mentioned him again, or close to that, even during Barrios' arc.
The cause of the conflict is dead and forgotten and it caused the kingdom to almost collapse.
(You don't need to explain real life events, I studied history in school, thanks.)