What about a blade that grows longer for the soul of each major enemy defeated and grows a new voice or aspect of personality based on who was killed.
It's a weapon broken into pieces with each separate shard adding an inch or two to the blade and turning it into a longer and stronger weapon with each extension.
Each effect the blade has can also vary on either the shard that hits the opponent.
Example, The tip is the very peak of the blade making it the easiest shard to get a strike with.
The protagonist would put the shard that would help them the most at the tip (fighting an ice golem? You'd use a fire tip.) You can also get creative, Using a spectral tip that makes your blade willingly phase through objects to cut through magical barriers or physical shields.
So basically the title. I'm looking for a cool anime weapon that a "god" could provide to a champion of his. I want it to be easily recognizable from a specific anime, but still vague enough to not violate any copyrights.
The champion is a warrior that uses sword and shield. Any ideas? And it doens't need to be anime specifically. Any pop-culture sword. LotR, game of thrones (I've never read it, and only watched half of season 1), etc. All ideas are welcome. There's just too many for me to decide between specifically.
So in short, what weapons would YOU geek out about being represented in a webnovel?
Or if that doesn't tickle your fancy, What about a sword and shield that can be merged together to make a mechanized axe.
Look up the Switch Axe from monster hunter to get the idea.
That's my favorite moment, having supreme weapon, but Excalibur is only as powerful as the heart and will of its wielder. So when they get power hungry... 
