It's a (very) light fog, was it in render or post?

It was in render. I edited it in post because it was obscuring the figure too much

He looks like very determined, and I like his outfit and the decor with the fog !

What is his outfit ?

Thanks. The outfit is shadowsoul m4 outfit

The gallery won't let me post a link but you can get it in the freestuff here

the fog looks great also like the character

I like the fog effect (and the grumpy but determined looking character!)! Did you use the Depth Cue or Volume method on the Atmosphere node? I don't know much about the Volume method b/c I'm not patient enough for the long render times, but with the Depth Cue method you can set a "start" distance for when the fog effect should begin, so if you're finding that it starts in front of your main character, you can increase the "start" distance value. It takes a fair amount of trial and error. The "end" distance is when the fog effect will completely obscure anything else in the background, so the bigger the difference between the "start" and "end" values, the thinner the fog.

I used the volume. It turned out too strong and fogged the figure too so I rendered only the foreground items without the volume and post worked them together. I usually let a render run overnight. Some only take a couple of hours, others take much longer. Some, I render in parts over several nights.