For: necromancy, a warped depiction of death and the afterlife, cross dressing, and wizardry and occult elements
The Return of the King has everything the previous Lord of the Rings movies had, plus multiple, incontrovertible counts of abomination before God. Where the earlier movies played with unbiblical ideas but left just enough room to keep them at really bad instead of really, really bad, The Return of the King, the most epic and most powerful of them all, throws everything it’s got into the battle against evil, and ends up becoming, itself, one more force of evil on the battlefield.
Necromancy is deliberately communicating with or even summoning the dead in order to access their power. Necromancy, in any form, for any purpose, and by any person, is an abomination.1 It is practiced by the hero of the story, the titular king Aragorn.
Necromancy is strongly advised by a positively-portrayed character as a solution to the too-small army. Aragorn is initially hesitant, but only because the dead ones in question are murderers and traitors, not because they are dead. Aragorn does, in a major turning point in the movie, deliberately seek out contact with the dead, and this act is called, both by Aragorn and his advisor, “summon[ing]”.
The dead appear and respond to Aragorn’s claimed influence over them. Aragorn vows to change their eternal fate if the dead spirits give him their allegiance, fulfill an oath made to his ancestor, and give him their power in an upcoming battle. The dead agree and do Aragorn’s bidding.
As Aragorn prepares to release the spirits from his control, a friend opines that not maintaining communication with and control over the dead is a bad idea, because their power is so desirable. This idea is positively-portrayed, and is only hindered by the terms of the oaths made between Aragorn and the dead ones.
A Warped Depiction of Death and the Afterlife
The dead summoned by Aragorn are said to be in a state of unrest because of the curse of a man, and the curse is later revoked by a man. Biblically, however, no human has the ability to keep a saved person from entering rest after death. On the other hand, the ghosts are implied to be unsaved, and yet are promised that they will “be at peace” nevertheless.
The ghosts also continue to make moral decisions after death, which affect their eternal destinies.
The ghosts in The Return of the King are able to participate in the physical realities of this world, although they can at times opt not to. The dead also kill humans and other living creatures. Biblically, the dead are physically incapacitated with regard to this world, and are no threat to anyone. In The Return of the King, dead spirits have the physical advantage over live people. This view is warped and completely inconsistent with God’s truth.
There is implied annihilationism.
A strongly positively-portrayed character engages in cross dressing, and is so determined to do so that she commits treason in order to obtain the opportunity. In the original Hebrew, the biblical prohibition of cross dressing specifically implies women taking up the battle equipment of men,2 which is the exact context of the cross dressing in The Return of the King.
It is worth noting that there are no extenuating circumstances to the woman committing abomination, without appealing to a crass “the ends justify the means” perspective on morality. Her value as a human being was never doubted by any of the other characters, and her motives were certainly not self-sacrificial (sacrifice is by definition inconsistent with what one already wants to do).
Wizardry and Occult Elements
As in the previous movies in the series, one of the heroes and one of the villains of the story are wizards, not just in name but in practice. Wizardry is an abomination, according to scripture.1
Soothsaying (another abomination, biblically1) is practiced and referenced at multiple points during the movie, by positively-portrayed characters.
Totemism is a theme in The Return of the King, with inanimate but symbolic objects being imbued with strong magical powers when handed down through the right bloodline. A magic sword, in particular, enables the hero who inherited it to interact physically with the dead.
1 Deuteronomy 18:10-12
2 Deuteronomy 22:5