The weapon you have is a fantasy (again, not real) or in this context not real as in not used in real combat. It is a novelty item, nothing more, and have certainly not been used to kill anyone (assuming you didn't kill anyone of course
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Whether or not something is used in real life combat isn't really an effective measurement of whether or not it would have been effective against other weapons of a particular time frame. Not everything that's used is actually effective, and not everything that isn't used is actually ineffective. There are always good apples that get thrown out, and bad apples that get brought home to the table. Things like that just happen sometimes.
Let's take a look at muskets, for example. Crossbows and Longbows are definitely superior to muskets, even though they existed for centuries before muskets, and were discarded to use muskets instead. Europeans discarded their bows and crossbows and every soldier began using a musket, which was less deadly, less accurate, with lower range and a lower rate of fire, than crossbows, longbows, and compound bows, which were all functionally superior to muskets, and were definitely superior to the sorry excuse for a pistol that people were using back then.
People don't always use what's most effective. Just because something isn't used, doesn't mean it isn't effective. Sure, people didn't use this blade. People also stood in lines and took turns dying, politely waiting their turn to attack.
This blade could certainly be effective in combat. The way it is shaped would allow the wielder to parry an opponent's attack, hook their weapon in one of the notches, and disarm them. A disarmed opponent then doesn't stand a chance, and the weapon has long points to pierce through armor and kill the target.
The reason things like this weren't used has nothing to do with whether or not they would be effective. Things like this would be incredibly difficult to make with a hammer, and additionally, people weren't trained to use this weapon; they were used to swords and axes. There wouldn't be demand for something like this; people wouldn't want it, and people would definitely not want to sit around with a hammer trying to make something like this when they don't even know anyone who would want to take the time to learn how to use a completely new weapon.
Let's take a look at cultures around the world. It's clear that many types of swords, including the gladius, the katana, and the claymore, were very effective, and people around the world traded with one another and had access to these different weapons. So why is it that Europeans didn't start using Katanas, and Japanese people didn't start using Claymores? Because they already knew how to use their own weapons. Why would they want to take the time to learn how to use a completely different blade when they already knew how to use the normal ones that everybody else around them used? The same goes for this sort of blade. It would probably be effective if someone trained to use it, but why would anyone dedicate their life to learning to use a weapon like this, risking it being a waste of time, when they could just dedicate their life to learning how to use what everybody else uses, and function in unison with them? It's just how it is; when it comes to weapons, people tend to choose the same things. They don't even know why they do it; they just do, because everybody else does. A large part of why the native americans were unable to fight off Europeans was because they gave everything they had to get their hands on muskets, when what they should have been doing was using their simple bows, which would have silently and effectively fought off the threat. The muskets were their downfall, but they wanted them anyway, because everybody else used muskets, and if everybody else does it, it must be the best, right? Sadly, no.
I'm not saying this would be the almighty weapon that changes the fate of the world. I'm just saying, don't write something off just because it wasn't popular. If time's proven anything, it's that the majority has always been really good at making poor choices and having poor taste. Heck, just listen to what people are calling music these days.