Soul Swords are swords with the soul of a dead person bound to it by a necromancer*:
Assuming you have the "sharp eyes" trait and can see and communicate with these souls**, I'm guessing the point of the decision is this: Which soul do you want to help?
With that in mind, here are my takes:
- If I help the grandma share her recipes with her loved ones, maybe she'll share them with me, too!
- I could probably help the school teacher get revenge on his students, either by killing them with the sword or another way.
- The super fan would definitely appreciate me finding their favorite book series and reading it with them from beginning to end.
The latter two would be really fun adventures, but I think I'll take the grandma soul sword! I'd really like to know what those recipes are!
*Not to be confused with swords that have their own artificial souls, which are blends of multiple souls of people, created by wizards: