'Not fulfilling my headcanons'
One of my headcanons about BM aside from her being pure elemental wizard queen instead of brutish raw strength woman :
Charlotte Linlin, The WSS since Blank Century, she is a fragile, wise and kind, a beautiful and forever-young perfect swordswoman, tall and slim in figure, who had lived since almost a thousand years ago, her vampiric sword absorbing souls, lifespan, and health from animate or inanimate objects alike due to her extending soul-manipulating ability to her sword.
Having perfected the songs of the sword since 800++ years, she actually likes to tell stories of the old, and very pleasant to open up and become a great reliable ally to the Strawhats, after Luffy did the impossible and beat the WSC, Kaidou. She gives the Strawhats an extremely valuable information: Imu's Identity and Goal, and she also gives Nico Robin the hints for putting the Poneglyph puzzle pieces together.
@Den_Den_Mushi maybe this can trigger some additional ideas for you to write since i'm not confident enough in my grammar lol