As it says in the title: Can a Warforged (Monster Manual III, P190-191, 215, Eberron Campaign Setting, P20-24) become a vampire or vampire spawn?
My research shows that a living construct type is immune to energy (level) drain, but is subject to ability damage/drain and necromancy effects.
A vampire's Create Spawn ability states:
A humanoid or monstrous humanoid slain by a vampire’s energy drain rises as a vampire spawn 1d4 days after burial.
If the vampire instead drains the victim’s Constitution to 0 or lower, the victim returns as a spawn if it had 4 or less HD and as a vampire if it had 5 or more HD.
As a Warforged cannot be energy drained, and is not a humanoid or monstrous humanoid, that means of causing it to become a vampire spawn should not work. However "the victim" in the second paragraph is suggestive that it may apply to any victim.
However, MM 252 states:
“Vampire” is an acquired template that can be added to any humanoid or monstrous humanoid creature (referred to hereafter as the base creature).
Given that a Warforged is a living construct and not a humanoid (monstrous or not), I would guess that it cannot become a vampire, despite being subject to a vampire's Con drain and necromantic effects?
Is my assessment of the rules correct?