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"Occhan" is a humble middle-aged adventurer who makes a living accepting jobs from a guild in a certain town. But his true form is a "Shape-Shifter," a dungeon monster. He used his transformation abilities to live a carefree second life in a peaceful human town. Just as he has acquired the life he wanted, he lets his kindhearted nature gets the better of him and he finds himself poking his nose into all kinds of troublesome business. But every time, he uses his transformation skills and his experience in the "monster world" to resolve one incident after another.
A high school student, who likes to camp solo, travels around the other world freely! One day on his way home, he is summoned to a different world. After graduating, he decides to go on a trip somewhere far away, and he thinks, “This means I can go on an indefinite wandering trip to a different world in the style of medieval Europe”. He decides to return to the other world after enjoying the unknown world of swords and magic, and blends into the other world at an astonishing speed, using magic and physical enhancement at will. What’s more, it seems that the magic he can bring to life by utilizing his knowledge of survival on Earth is far beyond the common sense of people in other worlds. What kind of magic was that? The original, improved magic?
Nine spends his days as a vanguard in a party that found him, but he and his beloved cat, Enu, are forced to do all the chores. However, one day, the leader sells off the black sword, a memento of Nine's father, without permission, and uses violence against his precious Enu and Nine's patience reaches its limit! "I'm quitting now!'' Nine, determined to leave the party and start a new life, is suddenly confronted by an S-rank adventurer "Dahlia the Flash''. And then he is scouted by the strongest party on the continent, "Red Hawk"...?