Arcanadaemon, Charon, Charonadaemon, Derghodaemon, Guardian Daemon<>, Hydrodaemon, Mezzodaemon, Nycadaemon, Oinodaemon, Piscodaemon, Ultrodaemon, Yagnodaemon.

Daemons inhabit the Lower Outer Planes of Gehenna,
Tarterus,
and the Glooms of Hades. <link & darken>
There is a large number of daemon races,
each race dominated by its strongest and most intelligent member.
Weaker races are usually at the beck and call of stronger members of their race,
while the strongest daemon, the Oinodaemon, rules all. <C>

Daemons resemble both devils and demons,
and they will associate with either for their purposes.
Daemons may move throughout the Lower Planes from the Nine Hells to the [Abyss] and may travel through the Astral and Ethereal Planes.
They may not enter the PMP or any of the related Inner Planes without [aid], <l>
such as by conjuration, summoning, or a [gate].

Lesser daemons on any plane may be slain forever,
their spirits reincarnating in a different form after death.
Greater daemons can only be truly killed on the 3 planes to which they are native. <3 layers of the plane of Hades?>
Slaying a greater daemon elsewhere merely sends its essence back to that home plane and its material body re-forms over a long period of time (1 year per hit die).

All daemons have personal Names by which they may be summoned and controlled. <C>
Lesser daemons have a single name by which they may be commanded,
but greater daemons have many personal Names, <C>
all of which they seek to keep hidden from other powers in the [Abyss] and the Hells.
A greater daemon has a 5% chance to hear the summons of some mortal speaking its Name and investigate. <C>
The speaker of this fell name should prepare to deal with a powerful daemon who will seek to return the name to secrecy,
usually by slaying its betrayer.
<s>

A pentagram will protect the summoner from daemonkind.
Daemons do not like service to weaker beings,
but given a strong,
evil leader and a sufficient reward,
they may enter into an alliance,
making themselves the superior partner.

Each type of daemon has its own separate abilities and characteristics,
but all daemons have infra- and ultravision <link for both> and share the following spell-like abilities:
    [detect invisible] <link>,
    [read magic],
    [comprehend languages],
    [invisibility],
    [telepathy] (with creatures of low intelligence or higher),
    and [word of recall] (once per day, back to their plane of origin).

Daemons,
unless otherwise noted,
are affected by the following attack forms:
    acid (half damage),
    cold (half),
    electricity or lightning (full),
    dragon or magical fire (half),
    gas (full),
    magic missile (full).
    Enchanted iron and silver weapons do full damage;
    poison,
    paralysis,
    and normal weapons do no damage.

All daemons have a special form of magic resistance.
The listed magic resistance is the resistance to 1st-level spells and decreases by 5% for each level above 1st.
All magic resistance is still versus an 11th-level spell-caster.
    For example,
        a 12th-level magic-user casts a 5th level spell at a daemon with 100% magic resistance.
        The real magic resistance is 100 minus 20 (5th-level spell vs. 1st) minus 5 (12th-level magic-user versus 11th) equals 75% magic resistance.
In addition,
charm and [suggestion] spells hav eno effect on daemonic life.

This magic resistance affects magic items used by daemons and the magic is treated as a spell of a similar level.
    (For example,
        a daemon using a [wand of fireballs] must fail his magic resistance roll to use it,
        treating the wand as a 6th-level spell). <x in text : added (>
For this reason they shy away from most magical items but will use magical shields or weapons,
which still have their pluses to hit or defend regardless of the magic resistance of the daemon.

Quote:
Originally Posted by Gray Mouser
2) Can all demons and devil possess someone or only certain types (presumably the more powerful ones)?

It is up to the DM, but I'd say that those of 5th rank or above can attempt possession as if casting a magic jar spell.

Quote:
Originally Posted by Gray Mouser
3) Do you envision Daemons and Demodands having this ability, or is it limited to the creatures already mentioned?

No and yes.