Expecting visitors from all races to come calling after learning that Rimuru now controls the entire Great Forest of Jura, Rimuru decides to hold a festival to introduce himself and Tempest to the world, with the goal of attracting new citizens.
Oh, I get it. He got stuck 
cleaning up the aftermath.
فهمت. غَرِقَ في تنظيف المُخلّفات
Ah, ich verstehe.
Er hat ihm das Aufräumen aufgedrückt.
Conque le dejaron el trabajo a él.
Conque le ha endosado el trabajo.
En gros,
elle lui a refilé la corvée de ménage.
Capisco. L'ha incastrato
a gestire le varie faccende post guerra.
Entendi. Ele ficou responsável
por limpar a bagunça.
Ну понятно…
на него спихнули разгребать итоги войны.