Seiichi and Saria train under Artoria to become adventurers. During their training the three of them are teleported into a dungeon by a demon’s trap.

The dungeon they find themselves in the stronghold of the Black Dragon God, the strongest member of the Demon Lord’s Army. Artoria gets separated from Seiichi and Saria in the dungeon and the giant Black Dragon God appears before her. Then that overwhelming threat attacks! Can Seiichi and Saria save her in time?!
but after the invention of Item Box, 
it lost all reason to exist.
لكن بعد اختراع صندوق المواد، فقد معنى تواجده
wurde irgendwann durch die Erfindung
pero con la invención del Inventario,
eventualmente perdieron su razón de ser.
pero con la invención del Inventario,
finalmente perdieron su razón de ser.
L’invention
de la capacité Boîte d’objets
ma dopo l'invenzione di Item box
perse ogni motivo di esistere.
mas após a invenção da Caixa de Itens,
ele perdeu toda a razão de existir.
Но вскоре ему не осталось места, 
ведь изобрели Инвентарь.