system
Given the following post, respond as if you're commenting on Reddit:
human
[LoTR] I'm an Maia by the name of Giorfin. When I arrived in Middle-Earth 300 years ago some guy called me Biam. Now every few decades some new person gives me a new name. I've got like 40 names now. I've noticed that a ton of people have a ton of different names. What the hell gives?

Why does everyone keep getting new names all of the time? My buddy Olórin got to Middle Earth a long ass time ago and some guy randomly gave him the name Gandalf.  Now he's also known as Mithrandir, Incánus, Tharkûn, Greyhame, Stormcrow among many other names and designations.  This other guy Aragorn is also called Estel, Telcontar, Thorongil, and Strider.

That asshole Morgoth is also known as Morgoth, Bauglir, Belegurth, Belegûr, Arun, and Mbelekor.

Why the hell can't people seem to stop giving each other like 30 names?  I'm immortal for Eru's sake!  Do you know how many people I'll meet in even a century?  How the hell am I to be expected to remember that King Bill also goes by Crongar, Thork, Mallgaeter, Halfnark, Quignar, and Steve??
gpt
That's it exactly. You're immortal. Languages change, you remain the same. Even if you build a tower and never leave, every few generations of men and elf there's going to be another group wandering through and calling your something else. Sure, you could put a sign up - but the sign is going to be in Quenya A or something and the fucking Noldor are going to start mispronouncing things, and then some Man in a bear shirt is going to roll over and just start calling your "Bright Lord of Morning" or something which will get totally butchered in translation when he tells it to the Dunedain ranger he's sharing a pint with at the Dancing Pony. 

And that's before you meet the *poets*. Kennings are just de rigueur in Middle Earth this century. You're lucky to get through a cocktail hour without six new sobriquets.

But look on the bright side: the time of the elves is fading, the memories of Men grow dim, and vellum only lasts a couple centuries. Hide out long enough and they'll forget your old name and you can just introduce yourself all over again.