If I do make a page for YYH, I probably won't put much series info, just fanfic links and stuff.  Mostly Hiei x Kurama fics *grin*.  I actually don't know too much about the show itself, but here's a bit of what I know.

    There are three worlds:  the ningenkai (human world i.e. earth), the reikai (the spirit world, kind of like heaven but they process souls for where they should end up, and souls don't stay there.) and the makai (the demon world).  The god of the Reikai is Enma, but his son, Koenma, is really in charge of a lot of stuff.  The Reikai is where souls end up after a person dies.  Koenma is usually in the form of a toddler, but he also has an adult form.  He always has a blue pacifier in his mouth (the pacifier collects his energy) and he has "Jr." written on his forehead ("Jr." is kind of the equivalent of "Ko", so it's Enma Jr., get it?)  Koenma also has to manage the barrier between the Makai and the Ningenkai, and to help he has tantei, or detectives.  The Tantei are as follows:  Urameshi Yuusuke, he's a human with demon ancestry. He died once and was resurrected, which is how he met Koenma.  He uses Rei Gun, which means he shoots his reiki (spiritual energy) out of his fingers.  Kuwabara Kazuma is a regular human, but he has some psychic powers.  He uses a sword made of his reiki.  Minamino Shuuichi is a very polite and kind boy with long red hair and green eyes.  But he's got 2 other forms, a silver kitsune (fox) with, like, seven tails; and a youko (fox demon) with long silver hair, golden eyes and furry dog ears.  His youko name is Kurama.  Kurama can control makai plants and uses the Rose Whip.  Hiei is a fire demon, but the rest of his clan were ice demons, so he was banished.  Hiei is kind of short, but very fast and good with a katana.  He has a jagan in his forehead, which is a kind of eye and he can search for people with it.  He also has a Kokuryuuha (?) on his right arm which is a magic black dragon.  Both his forehead and right arm are warded under bandages.  Hiei was looking for his half-sister Yukina, who is also looking for him.  Yukina doesn't know Hiei is her brother, but he knows who she is.  Yukina has healing powers, and also Kuwabara has a crush on her.  Botan is a ferrygirl for the Reikai (which means she goes to get souls after a person dies and brings them to the Reikai.)  She is also an assistant to Yuusuke.  She flies around on an oar and she has long blue hair in a ponytail.  Genkai is an old woman who trains the tantei.  I don't know much about her but she lives in a temple with Yukina.  Keiko is Yuusuke's girlfriend.  They quarrel a lot.  She's just a regular human, no special powers or anything.

    Okay, so even though I claimed to not know much about YYH, it actually seemed to add up to quite a bit.  The only thing is that it was all character info and not much plot info!

Hiei and Minamino Shuuichi

Youko Kurama and Minamino Shuuichi

The above images came from:   The Page of the Lonely Fox    and    YYH's EVERLASTING ROMANCE