The spider may be her bio dad but mr. litch was the one who raised her and loved her. he is more of a dad then the outher dude will ever be KICK HIS ASS FOR HURTING YOUR BABY
Awesome dad aside, I do like the idea of yokai not realising how many humans there are and so they just believe there are a couple of immortal, unstoppable humans.
That's the idea of Gashadokuro in a nutshell; Bone Daddy dropped a big hint about it way back in the flashback to when he and Taya met, when he said he was tired of having all these memories of families that were gone, and not knowing which one was his.
No uncertainty, now.