This is an awesome idea, but looks a bit confusing. The middle part might as be missing, if only the side blades are doing the work, OR the center blade acts as foundation which dampens the resonance put on the side blade, and does prevent them to resonate OR if the side blades are damaged, maybe the center can act as a lighter and slimmer sword, used for dueling dexterous opponents rather then being a meat cleaver, like when the side blade makes the sword three times bulkier...

I had a fun idea, with the design - essentially twisting it around and making the center piece the removable one: Leave the center blade out, and only have the side ones present, forming a two edged fork, which can resonate/hum like a sound fork and do more damage...like the Vibroblades from Star Wars. But, when needed these side blades can twist inward 180 degree and form the more slimmer blade and using the inner side of the fork-blade for a fresh cutting experience! And maybe the yet present center part would be the one which can be added to add mass and damage when a wielder can handle the weight of such a beast of a sword, but otherwise the center piece could be resting in the scabbard on the side/back of the user. This way, you have a double edged mode with the fork and slim design which can be serrated blades and straight one or whatever, and the third Heavy Damage Dealer mode with the center added if needed.

Made me think about this, so the concept is cool!

From your words, as they say, I sit with a face on my face, I definitely like your thoughts. In terms of swords, I also had an idea to make some kind of hybrid thread so that a small wave of sound could come from it, like from, for example, a tuning fork and at the same time the metal is extremely fragile - why is such a sword needed? Against some specific enemies that are sensitive to sound

Would be good to shatter, glass and ice walls, or to damage crystal-structured creatures/elementals and maybe those who get around and hunt by echolocation like bats, giant bats, and deep creatures. You could mislead a worm creature by launching a sound-blast away from you, and dash in the other direction hopefully for safety.

Hehe, you just guessed with the one I'm going to show now :D

I love RPGs and D&D in particular, and my most fun of it is both the bestiary and the weapon/tool interaction with the world. I also love custom designs which aren't too obviously overpowered, but more like super good to deal with one thing, and does normally/well-enough with anything else.

One day (maybe in 2023) I will ask my artist friends to make a sword design of my own development. Sword is OP on it's own, but also be able to shatter and get chipped, so maintaining it is worth it, yet using it are very good against spellcasters and creatures who are weak against cutting damage. Still doing reduced damage against golems/skelletons and alike, which require a war-hammer or something alike. I tried to balance it to be both a very good sword, but nothing too more...*sigh* Someday, it'll be presented. =:3