Wanda gets no bonus from the Thulecite Bat when at older ages.
I know the Thulecite bat isn't exactly pure nightmare fuel like the dark sword is, but considering it utilizes nightmare magic and spawns shadow tentacles I feel there should be some kind of buff when using the thulecite bat. Perhaps higher chance for shadow tentacles to spawn? Could be a neat addition!
1. Use thulecite bat as Wanda
2. Notice there is no difference between damage even if you're old and young, despite it being a weapon that heavily utilizes shadow magic