This story takes place before Rimuru's reincarnation. Shizu, also known as the Conqueror of Flames, responds to an urgent request calling her to the Kingdom of Filtwood. When she reaches the castle, many adventurers are already there. What request could have demanded such a huge gathering? It turns out a demon has been revived, and the adventurers have been called to subjugate it. It is said that more than ten of the most skilled adventurers have already been killed by this demon. But there is more to this request than meets the eye...
All the demons dwelling in the 
Kingdom of Filtwood were purged.
تمّ تطهير كافّة الشياطين في مملكةِ فيلتوود
Die Dämonen, die das Königreich Filtwood zu
ihrem Nest gemacht hatten, wurden ausgemerzt.
Todos los demonios que habitaban
el reino de Filtwood fueron eliminados.
Todos los demonios que habitaban
el reino de Filtwood fueron eliminados.
Les démons au pouvoir à Fiertöd
disparurent soudain.
Si occuparono di tutti i diavoli 
presenti sul territorio di Filtwood.
Todos os demônios aninhados no
Reino de Filtwood foram varridos dali.
Демоны, захватившие королевство Филтвуд,
побеждены.