This calligraphy pen sub tool is one brush you should have in your arsenal for quick render of your character’s hair. so without further ado, what a you waiting for … get it for yourself!
* Before you can start implementing that high-impact tool in Clip Studio Paint that captures the crisp, graphic edges essential for dynamic hair, it's crucial to customize the appearance and function of your "Calligraphy pen" with precision and finesse.
And before you start you hair draw, first make this necessary below settings, alongside you should make the color of the brush the able light blue color cause it impartial value.
Once you have done the above properly, you can effectively draw out Both the inner and out lines of your character’s hair.
> Base on how you use this brush you can create unique hairstyles with unique expressions to them.
> [ Also, after you have create your character’s haircut ]
> You can convert the Flat black and white color into a line art by either clicking on the “Black only button” located in the “Layer property”,
Or
You can simply convert the Layer “Blending Mode” to any of the Dark modes eg., Darken, Multiply, Color burn, Linear burn.

Once that’s done, the line art should now then be visible,

Of which you can now, render the hair color bottom of the line art layer as show below 👇.
Ease in & out taper end
With watercolor edge enable