Link to 3D model: https://sketchfab.com/models/44e355c0b8d94f7a8a59e5034d3bc3d7
This a a fantastic artwork created by a Japanese 3D artist Atsushi Tamaki.
I was amazed by the manga-outline effect on the character and have been trying to work out how it can be done, but no luck so far. What I can tell is that it seems like the character is coated by a one-side transparent coating(transparent if view from out side, pure black if view from in side).
Looking for some advice. Thank you!