First:
	The first moon kingdom - when did it collapse?  How much is known 
about the Earth kingdom that Endymion came from?  And Beryl, powered by 
the supernatural Metallia - whe was from Earth, too, right?
	And if I remember - the assault on the moon kingdom was from 
Earth, backed up by various demonic forces - or am I wrong?  Any word of 
what happened to the other planetary kingdoms?

   Beats me.  All I know of SM is from the DIC version.

	Second:
	Yokho - 108th (?) demon-hunting descendant, current in a long 
line of mamono slayers

   *This* I can help you with.  Yes, Yohko is the 108th devil hunter in the
Mano line, though, as someone else pointed out, Yohko's mother *should've*
been 108th.

(BTW, what's the diff. between a youma and a mamono?).

   I'm not sure myself.  Devils have been referred to as 'mamono' and
'youma' interchangably in DHY.  (Watch DHY6.  When Yohko and Ayako become
aware of the demon, Ayako exclaims, "Youma!" (assuming you're watching the
subtitled version.))

 Is it ever said who was the first hunter?

   Yes.  In DHY5, Yohko goes back in time and meets the very first devil
hunter, a young woman named Haruka Mano.

 Who established the line?  Why?

   This isn't established in the animes I've seen.  I figure Haruka either
found an ancient artifact (the Mano Youma Ring) and discovered how to use it
to fight devils, or it was bestowed upon her by a god(dess) who wanted to
keep the power of the demons in check.

 Are there other family lines of demon hunters?

   Yohko has an apprentice named Azusa Kanzaki.  When Azusa becomes a
full-fledged devil hunter, she will represent a new family line.  I think
it's a safe bet that there are other lines of DHs out there.  There are just
too many demons for one or two teenage girls to handle alone. ^_^

 A good page 
where I can read up on this stuff?

   Ummmm...I'm sure there's one out there... ^_^;;

*******************************************************
* Kent Magami and David Outram (kmagami@hsonline.net) *
*Second Deacon of Ryoga, Tracker of the Wandering One *
*Co-founder and High Priest of the Holy Order of A-ko *
*      Motto: You can *never* have enough C-kos!      *
*******************************************************
*    One month after B-ko hypnotized C-ko...          *
*                                                     *
*    C-ko:  Hi, B-ko!  What're we gonna do tonight?   *
*    B-ko:  The same thing we do every night, C-ko--  *
* try to destroy A-ko!                                *
*    C-ko:  Waiwai!!!!                                *
*                                                     *
*    o/~ One of them's an airhead; the other one's    *
* insane!  It's C-ko and the Brain! o/~               *
*******************************************************