Hello Guys. Please help. I dont know how to make my scene darker in unity2d. because what I want is to make my character use light. so I want to make a scene in Unity2d that looks so dark.
Thanks in advance 
The simplest way is to add a transparent UI overlay filling the screen, and change the color.
Simply create a black rectangle png approximately the same ratio as your screen (doesnât have to be exact). You can make it slightly more transparent in the middle to give the âvignetteâ look (darker on the edges).
Add the png to an Image component, set the alpha to what you want, and youâre set to go.
You can also simply use the standard assets Vignette camera effect.
I would advice changing the ambient light.
If in your case the light only comes from the character, then setting the ambient light to color (black), then your scene is completely dark.
no magic ! just add a material to the sprites & set the shader of the material to âSprites/Deffuseâ & then use & manipulate lights if you want to make objects visible in some places & in other not