An isekai novel. A forty year old professional dies and is transported to another world as his Dungeons and
He wakes up in a cell, discovers that the bandits holding him are led by a sorcerer who rages at him because his staff is magic despite having no mana, makes use of the spells he had prepped (apparently he was sent ready) to save himself, and rescues their prisoner, a merchant's daughter held for ransom, who can fill him in a little.
It goes on, with other sorcerers reacting in their ways to his magic, with their escape being complicated by this world's demons, with his actually witnessing what the spells he has would do according their descriptions, with assassins and orders of knights and his making an unpleasant discovery about demons, and many more things.
This may be an artifact of translation, but the writing struck me as a bit weak to convey what it depicted. Or maybe I'm just persnickety about style.