The mysterious girl that showed up out of nowhere was actually Filo. She's a filolial queen with an advanced transformation ability, and she can even take human form thanks to it. However, her clothes get ripped every time she transforms, meaning Naofumi has to get her some magic clothes if he doesn't want to go broke. The party leaves on a new adventure to gather the materials required.
I even managed to pick up some spells, 
thanks to getting a feel for mana.
وحتّى أنّني تمكّنتُ من تعلّم بعض التعويذات
بفضل فهمي للمانا
J’ai pu apprendre quelques sorts
car j’arrivais à sentir le mana.
E sono riuscito ad apprendere degli incantesimi
grazie alla percezione del potere magico.
Eu consegui aprender até algumas
magias depois de começar a sentir mana.
А почувствовав чары,
я сумел освоить и заклинания.