Okay, so this might sound a bit odd, but…What if Inkabelle is supposed to be a Suzuri no tamashii?
Hear me out, in some iterations, a Suzuri no tamashi come into existence due to inkstones being used to write the same thing over and over and over again. It is said that they will take the aspect of what the stories that have been written on it. In a sense, bringing their characters to life.
Halfway through Lucy’s introductory cutscene, when she begins to lose her creativity she begins to paint several self-portraits. The first one being a simple painting of herself pondering her next project
Next, she starts creating a repeating series of paintings that share the same position with little to no difference aside from the increasing stacks of canvases which imply that she painted the same thing in an innumerable amount of times.
The final canvas we see a monochrome painting that looked like it was done in a hurry. The last shot of Lucy is a canvas POV of her whipping a paint brush holding black paint indefinitely.
It should also be noted that a Suzuri no tamashii’s behavior can vary from, at best being extremely messy, at worst being very violent. With her throwing paint cans and summoning ink creatures it’s safe to say Inkabelle fits both of these.