Make a prefab with custom inspector into a dockable Window

Currently, I am using a Prefab + Custom Inspectors to input all of my database of enemies, items, skills, etc... as in Pic1:

What I want to do is to replace this with an Window, like Scene, Animation, Inspector...

But I don't know how to save whatever I write there, and have the data saved to persist through opening and closing the unity editor, play sessions, code hotswap, etc..

Currently, it works because I edit the prefab, and all data remains saved onto it. Just linking the prefab to the window is not enough to satisfy this question, I want to remove the prefab entirely and work only with this 'Database' window.

It's function should be akin to RPGMaker Database tab, pic if you don't know about it: