Is there a way to edit the outline color of a character?

[A1TA]

Her hair is circled in black, and her body is maroon. Is there any way to change this color?

[Tiersei]

You gotta import it into unity and change the outline color there.

[Kasplodicus]

https://github.com/vrm-c/UniVRM
This plugin for Unity.

https://github.com/absolute-quantum/cats-blender-plugin
Or this plugin for Blender

Either one will let you edit your outline color, rim lighting color, even add matcaps and emission lights.