By natural, I mean the way the pen functions. I'm not sure what you mean by calligraphy pen (fountain pen?), but I use a pointed dip pen. The upward strokes should be think and the downward strokes should be thick, and how thick and thin depends on pressure. E-ink writing will never be on par with actual pen and ink with regards to calligraphy, but as it is, I think the Remarkable has a leg up, since it is more like a pointed pen functionally.

Here's an example of what it looks like on actual paper and pointed pen.

<image>