If you have a home big enough to sport a man cave, then you have to get the decor right to establish it as that kind of space. There’s no set list of what has to be in a man cave, as every guy gets the freedom to define their space in their own ways. Having said that, there are common themes among man cave decor. For some, it is sports memorabilia. For others, movie props and paraphernalia rule the day. Oil, gas, and transportation items are big, and for some, weapons fit the bill.
A Blades Pro can sometimes be a nice touch, and for many reasons. Some guys just love having weapons of various kinds in their man cave, be they guns or bladed weapons, and a good Samurai sword, either real or replica, definitely fits into this vibe. If you practice martial arts, you might have some experience personally with such a weapon.
Of course you might also just appreciate them as a history buff, as someone with a passion and knowledge of Asian culture and history, particularly Japan. In another train of thought, such a weapon on your man cave wall might be an appreciation for a particular character from fiction, ranging from television or movies to anime and graphic novels.
If you do choose to mount a Samurai sword on your wall, do so carefully and mindful of the fact that you do not want pets or children disturbing it. Even a replica or unsharpened piece can prove dangerous as a falling object or used crudely as a clubbing weapon. Putting it inside a secure frame or clear yet locked cabinet is best in many cases, and can help protect the weapon from rust and dust over time.