Do you have the Dragon Archive CD set?If so, there's what's called a "series magic" set of daggers (as well as the originals of the Rings of Elemental Command, of which all copies are inferior). (Series magic is items that have their own individual powers, but by combining them, they gain new powers. Eg., Rod of Seven Parts, Arm of Valor (Ruins of Myth Drannor), and so on.)
Anyway, these daggers are simple daggers with a few powers. But touch two of the daggers together, and they combine to form a short sword, with a new power. Combine three daggers, and you have a long sword, with more powers. Combine four, and you have a bastard sword, with even more powers. And if you combine all five, you have a greatsword. With the power to open a gate to Tiamat's realm, allowing her to manifest an avatar on the Prime Material Plane......
How's that for a plot hook?
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