This weapon combo makes no sense, but hear me out.
String & Knife!
String would be able to be placed onto walls, floors, and players, being able to create traps.
With relics, this string would be able to set enemies on fire.
The knife however, is similar to the sword & knife combo.
BUT this knife can have string attatched onto it, able to be used as a psuedo grappling hook to swing on.
Attatching string onto the knife allows for it to be swung, like a flail to attack enemies.