So i looked it up and afaik this usage of the valkyrie glitch is not known by the public.
Yesterday i found out that the game does not check if a character has major holy blood, when a holy weapon is broken. So every Lance user for example can technically equip Gae Bolg when its broken (it does not work for drained tomes, because they cannot be equipped). When this weapon is repaired when equipped , you are not able to innitiate combat with this weapon, but you can use it on enemy phase and in the arena.
So i searched for a way to give this glitch a practical use. I tried to glitch a broken holy weapon via the valkyrie staff into the armory, but unfortunately those weapon get 34 uses even if they were broken. So i thought it is just not possible.
So in case you don´t know the weapon you want to glitch to the armory stays as an iron lance with 98 uses, unless you reset. So i was wondering if you are able to just revive that character and sell the glitched iron lance in the pawnshop and yes this works. This means you can glitch a weapon of your choice to an iron lance, revive and sell it, buy it with a lance user, equip it and save and reload the game. With this method you can equip nearly every weapon on every lance user and it has the same effect as the holy weapon example above (so only fighting in arena and on enemy phase).
There is in fact a method to get those weapons on none lance user, but its very unreliable and can corrupt your game. The valkyrie glitch does also affect weapons from characters that are not dead. So if you use the glitch on 2 characters instead of one, there is a possibility that characters in the castle are also affected by this. For example i managed to transform altennas gae bolg into an earth sword, thern i bought it with dermott, equiped it and after a save and reload he was able to use it.
With this i also managed to transform a brave bow into a blizzard tome. then i bought it with arthur and was able to use it. So as long as you dont reset the game (not sure what happens when you start a new chapter), you can also use the glitched weapons as if they were normal weapon, this is especially useful, because glitched weapons normally have an insane amount of kills on it. I got weapons with over 200 kills. For example if you are able to transform, lets say sigurds iconic silver sword into tyrfing, he can use it as a tyrfing.
This also helps you when it comes to inheritance. If Finn is Dermotts Dad, he can just buy swords through this method and pass them down to his son.
I tested this on a project naga translation and not on a japanese rom, but it shouldn´t matter.
Also i dont´t speak english often, so please ignore possible grammatical mistakes.