Half-Celestial PCs

[Tiberius]

Re: Rule #0

Also, remember that when an Outsider dies on the Prime, it isn't in fact "dead" it just gets returned to it's native plane. This is one of the reasons demons and celestials can afford to be so gung-ho when fighting on the Prime, other than an incoveniance, probably embarassament ("Hah-ha! Azifael got his butt kick by a paladin, agian!") they don't really suffer too much.

To the best of my knowledge, this is no longer the case. There are six ways to get an outsider to another plane: the Summon Monster chain, the Planar Binding/Ally chain, Gate, Plane Shift, Astral Projection, and Etherialness. The Summon Monster spells are of the Summoning subschool of Conjuration, and spells of that subschool are bound by the following SRD quote:

A summoned creature also goes away if it is killed or dropped to 0 hit points. It is not really dead. It takes 24 hours for the creature to reform, during which time it can't be summoned again.

The Astral Spell creates a new body for the creature on each plane while leaving its actual form on the plane of the casting, so an outsider who travels to the Prime Material by this method will not die when "killed."

Gate and the Planar Binding/Ally chain are of the Calling subschool of Conjuration, and thus subject to the following rule:

Creatures who are called actually die when they are killed; they do not disappear and reform, as do those brought by a summoning spell (see below).

Plane Shift and Etherialness move the creature bodily into another plane. As such, they are as vulnerable to true death as a PC planewalker is.

-Tiberius