SHADE: Narun Oil | MAG-HAMMER Online Store

After applying your base or layer colors, just apply Nuln Oil.

This will darken the colors and allow the shade color to collect in the recesses of the miniature, creating clear light and shadow for a good effect.
Once you get used to it, try shades other than Nuln Oil.
You can find an explanation of shade colors here.
If you're interested, please take a look.
https://www.makiwog.com/shadecolor-2/

*Some official product images are old and show 24ml, but the shade colors currently sold are 18ml.