What is the "Gift of Death" in Lord of the Rings

Elves do not have a proper afterlife. Their life is bound to Arda they are the life of Arda and Arda is their life. They are immortal as long as the world lasts because their Fea (soul) is strongly connected with their Hroa (body).

When they die of violent death or by grief, their soul goes to the Halls of Mandos and from there they get, after a while, incarnated in a new body (not reborn … this idea was revised by Tolkien: they get their old body rebuilt). They exit the Halls of Mandos (which is a physical place in Valinor) walking under the sun (or the stars) continuing their existence in the Bliss of Aman, the Blessed Realm.

Men, are called the strangers, because their soul does not belong to Arda, and that is why their bond with their bodies (which are made of the substances of Arda) is weak: this is why they suffer illnesses, and can easily die from wounds and, anyway, of old age within a few decades.

Once the human soul and body get sundered, the soul resides in the halls of Mandos in a separate room, and then they depart from the world, maybe (the following is partly speculation, partly non-canon material. The actual destiny of human souls is unknown even to the Valar) joining Eru himself which will instruct them in music so that they will take part in the fourth theme of Creation when the world will be created again, this time, perfect.

For sure when a man dies, his elf friend will not see him again, ever, in any form.

Whereas elven lifespan is made of eternal contemplation, bliss, and eventually melancholy for memories of past beauty, human life is short, afflicted by pain, diseases, weakness and haunted by the fear of the unknown (this last part is due to the lies of Morgoth who made Men fear their afterlife destiny).

In time both elves and Valar will get overcome with melancholy, they will grow terribly weary of their long existence, especially since the advent of the 4th age, when their part in the song of creation will be over and they will retire in the Blessed Realm. Then they will envy the gift of Men, the liberation from the burden of this perpetual, unchanging life in an unchanging world.

Moreover when the world ends also their life will end (since it is bound to the fate of Arda) and it is not known what role they will play if any.

Tolkien had a taste for melancholy, he would define it as “the joy in being sad”, he would say that “love is now mingled with grief, but because of it, it grows perhaps greater”… not being constrained forever to the circles of the world, searching liberation from the burden of desperation instead of clinging to life against the design of god (which is what the black Nuenorean and the Nazgul did) is in his world a bitter-sweet relief.

These are the last words of Aragorn to Arwen on his death bed:

As Aragorn felt his life drawing to a close, he came to Arwen, saying, “In sorrow we must go, but not in despair. Behold! we are not bound for ever to the circles of the world, and beyond them is more than memory.” When Aragorn realized that the hour of death was nearing him, he willingly surrendered his life rather than be torn away by force.

Beyond the circles of the world there is more than memory… Human afterlife, says Aragorn with the touch of foretelling that he always had in life, is more than being alive forever embalmed*) in a perfect land recalling a past of glory (which is the doom of Elves), it is a new life where, at the very least we will be free from the burden of this world.

This for sure is already a gift (at least on the eyes of the immortal ones), the joining with Eru outside the circles of the world is only a guess but a good one (being the theology of Tolkien’s world by a good measure derived from the Christian one), and that indeed would be the ultimate Gift.

*) Tolkien would define the Elves as “embalmers” as they were created to preserve the world and they ended up in the vain endeavour of opposing any sort of change in a fast-changing world, that is why they left Middle-Earth to join the Valar in the Blessed Land where everything is unmarred and unchageable.