I'm looking for any Manga or Manhwa which supernaturals play "second part" in the story...

• Supernaturals aren't the main story but take a second part of it.
• No action or fighting depends on supernatural powers.
• Slice of Life genre.

... Something like Melo Holic Manhwa, as an example.

Orange Marmalade?
The supernatural aspect isn't completely on the back burner but it is slice of life.

It's "the supernatural" not supernaturals.

Fruits Basket fits that, but looks like it's on your unfinished list...

How about another webcomic: Orange Marmalade
The female lead is a vampire but this aspect is downplayed and very low key... a secret to add spice to what is otherwise very much a school life/romance/drama.

edit: lol, I was beaten to it. left the window open too long before replying.

Himitsu no Kaidan has some ghost characters on the side from time to time.

The Voynich Hotel and Nickelodeon both have supernatural occurrences happening on the side that's treated as mundane. Though they are also pretty important to the stories themselves, too.

Acony and Blood Alone both focus on supernatural creatures, but it is slice-of-life, and the supernatural is usually downplayed. The same can be said for Kamichu!

Hikaru no Go

maybe:
Helen ESP
Himitsu no Kaidan
Nazo no Kanojo X

[img]https://c1.staticflickr.com/1/753/22668593615_519ce54b81_o.png[/img]

Maybe
How to hug an elephant

Chokotto Sister

What I like in Trivial Pursuit style. Pick your category:[img]http://i379.photobucket.com/albums/oo233/Reid4891/Manga/trivia-1.jpg[/img]

I second Fruits Basket

Also try Houkago Hokenshitsu - It isn't really supernatural, more a split between a nightmare world and the real world, but you may like it as the focus is on the relationships of the 3 main characters more than the nightmare world they visit. (Trust me, it becomes clearer when you read it,)

Shinrei Tantei Yakumo - Yakumo has a supernatural ability which he uses to solve mysteries and crimes, but I feel that his intelligence and deduction skills are more valuable and his ability seems to be there mostly for the overarching plot line. I wouldn't call it a second part, but it also isn't the be all and end all either.

That's all I can think of. It is really hard to find a supernatural manga where the powers aren't the main focus, sorry. 😢 I hope these help, even if they aren't exactly what you're looking for.

The pen is mightier than the sword...and considerably easier to write with.