モブから始まる探索英雄譚

Kaito Takagi is an unremarkable high schooler who farms slimes for pocket money in the dungeons that have opened across Japan. Then a golden slime he has never seen before drops a servant card, an item rare enough to be worth a fortune and able to summon a being out of legend. What Kaito summons is Sylphie, a small girl in valkyrie dress whose skills turn out to rank among the strongest anywhere, and his days as background scenery are over. This light novel is the source of the manga adaptation of the same story.