One of the most underappreciated weapons ever. Even though it has so much potential. It has all the pros a cane has, but with aerial support potential and defensive capabilities included, and it's stylish while at it. Also the combination potential is huge.
Combine it with a gun and you have fortified artilery when spread out, use it as a hidden blade like a sword cane and you get the shield included, even using it as a drill seems possible enough. A rotating umbrella would pretty much be a chainsaw...
Anyway. Watching this thread with interest. I'm thinking of planning a new story since my draft for my first one got waaaay too big for a first project, and an upgradeable umbrella is pretty high on the list of potential weapons for my MC. The more I think of it, the more it sounds way too OP. Sword & Shield, Gun, Aerial transport, Drill, Chainsaw-y Thing used to hack at enemies... aside from the obvious use of being a magical catalyst in the same vein as wands and canes in fantasy stories...