Do you think there is more lore about the Shadow Realm we don't know about? If so, what your theories?

What if Magica created the shadow realm?

Cool theory.

I am starting to think those Tuplas aren't only creatures in the Shadow Realm in my opinion. But I might be wrong.

Lena is not the only inhabitant of the shadow kingdom, there may be others! For example, I would like there to be another character (my fantasy): Rico is the younger twin brother, who will be the complete opposite!

I think they're would be a Shadow Guardian that takes over the Realm a creature that is a tall shadow figure that glooms the realm. I'm not sure if Lena knew about the Guardian of the realm. It would probably be mad if Lena is now out of the Shadow Realm.