I have an idea for a weapon type called a trick weapon. You could not buy these weapons you have to build them. What you would do is you bring 2-3 weapons ex scythe, chakrams, and war glaives. You would pick your main weapon - scythe and build the weapon like the scythe would detach its blades and handles to make chakrams and the scythe would also detach into war glaives. Is this possible, what improvements would you make and what would be your trick weapon
So basically you'd want one weapon that could split into multiple weapons. I've seen it done in some movies, like Clouds fusion sword in advent children. One giant sword that could slit into 7. but the way pathfinder is set up, at level one you are extremely limited by what you can do and a character like cloud would be a 20th level Fighter.
I mean if it takes a full round action to load a heavy crossbow, how long do you think it'll take to dismantle a weapon. I mean it takes a move action to just to draw a weapon.
also you have to think about how these weapons would be connected. It was never stated how the fusion sword in final fantasy worked. but, we can assume it involved some kind of future tech. maybe involving magnets or something. in pathfinder, the only thing that I can think of that would allow you to have a weapon that separates into multiple weapons would be magic.
I think that your best bet is to devise this as a magical weapon. also something that you have to keep in mind is free hands. what you have is a weapon that can split into three weapons and two of those are two handed weapons. so I don't really see how you'd use them effectively.
personally I would just use magic, but to use this ability you need a free hand. so you could have a great sword that as a move action, can split into a long sword and a short sword. this can be reduced to free action if you have the quickdraw feat. also maybe, you have to provide a slight of hand combat manoeuvre to pull this off otherwise doing so provokes attacks of opportunity.
So, Bloodborne?
Just steal from the game entirely, steal from the game entirely. Treat the weapon like its a double weapon in terms of enchanting and make it a swift action to swap between forms. This means they cannot change forms during the opponents turn, which emulates the small fraction of a second you're vulnerable in that game.
Also allow them to change forms as part of a standard action to attack. Use a custom craft skill.
The only Pathfinder weapon I know that's anything like this is the butterfly sword that can be separated into two.
About as close to this as it gets is Transformative as a magic weapon property, but that just changes your weapon into something the same size (as a standard action, I think?). Great for turning your scythe into an earthbreaker or a longspear, not as much when you want chakrams.
I wonder if a 'Transformative, Greater' would be a bad property to go for. Granted, the normal version is a flat 10,000 gp.
Otherwise, I'd probably ask for some idea from the player, insist on a bunch of Craft (weapon) rolls, and maybe magic if it's too out there. (Or the Master Craftsman feat and Craft Magic Arms and Armour.)