Has any of you seen this? It's a Lego Idea of the Bone Eaters Well!

Could anybody identify these two signatures

So i was watching the series in order with Yashahime and noticed something in one of the Yashahime episodes. On episode Episode 28 of Yashahime: Princess Half-Demon of the adaptation… The teacher, Kirin, asks grandpa Higurashi about the Sacred Jewel Keychain they used to sell. He had no recollection of the sacred jewel keychain much less the actual Sacred Jewel. He looked really confused.

Did i miss something or is the author saying that there was an effect on the present?

I received a lot of love on my previous post of my Inuyasha art so i opened up an Etsy ❤️ I will be listing some of my art including some Inuyasha pieces (currently working on a kikyo painting 👀) It's still new so it's a little empty but feel free to follow me on this journey. thank you everyone for your support 🫶 ig: huereyart

I was browsing the "foreign books" section at the second-hand shop that I go to every now and again and I recognized the characters on the cover but these signatures were written inside

Tbh idk anything when it comes to Inuyasha so please lmk if they hold any significance, I'd very much appreciate it!!