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?!
That single desire led it to grow limbs and 
gain the ability to speak and use magic.
أنبتت تلك الرغبة فيه أطرافاً، واكتسب
قدرة الكلام واستعمال السحر
Da wuchsen ihr Hände und Füße
und sie fing an, zu sprechen.
Ese deseo hizo que le salieran piernas
y manos y pudiera hablar.
Ese deseo hizo que le salieran piernas
y manos y pudiera hablar.
Sa détermination lui donna des membres,
le langage
Grazie a quel singolo desiderio, gli crebbero gli arti
e guadagnò la capacità di parlare e di usare la magia.
Esse desejo o levou a crescer membros,
ganhar a habilidade de falar e até usar magia.
За счёт сильного желания 
он обрёл умение говорить,