I'm not sure specifically as there could be many novels with that title or concept. It might be about a single individual who is extremely powerful and capable, like a hero who can take on an entire army by himself, perhaps in a fictional war or adventure setting.
There are some military - themed novels that might fit the bill. For instance, in some of the 'Jack Reacher' novels by Lee Child. Jack Reacher is a loner who often finds himself in situations where he has to take on multiple adversaries alone. He uses his combat skills, intelligence, and physical strength to overcome these challenges. Also, the 'Wolverine' novels in the X - Men universe. Wolverine, with his healing factor and adamantium claws, can be seen as a one - man fighting force against hordes of enemies.
It could mean that being a 'one man army', someone who tries to do everything alone, often leads to a 'dead end story', like a situation with no good outcome. It might imply that relying solely on oneself without support can be a path to failure or a hopeless situation.
Sure. In a business project, if a person tries to handle all aspects like marketing, finance, and product development alone (being a 'one man army'), they may soon find themselves overwhelmed. And eventually, the project might fail, which is the 'dead end story'.
This plot seemed to be similar to the plot in the Lord of the Rings series. According to the plot of the Lord of the Rings novel, this movie might be called The Lord of the Rings: The Return of the King. It described the battle between four different heroes in order to obtain a Lord of the Rings.
, I recommend 'Transmigration from gal is indeed abnormal' to you. This light novel told the story of an otaku who transmigrated into Yagyu Rin. A mechanical voice appeared in Yagyu Rin's mind, which meant that he was a natural protagonist. In the plot, there was the word 'Galo', which was probably the word' valiant army 'Galo'. I suggest you read this interesting novel. I hope you like my recommendation.😗