With regards to there being no mention of other bearers, that's why I said it's unlikely. From my point of view, though, if Celestia had four friends just as close to her as the mane six are to each other, I get the feeling that she wouldn't want reminders of the fact that she outlived them all prominently displayed in her own throne room. It's not egomania, it's attempting to avoid the pain of their loss.
I wonder. What if you had the scenario where one pony has a crush on another but is too afraid to admit it. Would Cadence's magic give them a shot of Dutch courage?
There's no need to sharpen my pencils anymore. My pencils are sharp enough.
Even the dull ones will leave a mark.
I prefer to think of the 'Dark Powers' that she spoke of were more Force-like than simply her making some deal with some unlikely devil character. Nightmare Moon was simply Luna but with crazy evil eyes.
Not a deal with the devil, but more like she evoked a sort of magic that she really couldn't keep a handle on, or at least, not in her current mental state. It made her really powerful, but continued her slide into madness.
I have a message from another time...
Huh. Well, at least I got the winter part right.
There's no need to sharpen my pencils anymore. My pencils are sharp enough.
Even the dull ones will leave a mark.
Anyway, my version of the other for bearers were raised as undead servants of Nightmare Moon and became the stars which aided NM's escape.
I've heard that theory before and it's never quite gelled with me.
I know we're talking about magical talking horses here, but for me it's too farfetched for a little pony to somehow transform into a colossal (like, hundreds of times bigger than a planet) ball of fire and gas.
Yeah, we're talking about magic here, but there's a limit.
"A toilet with the potentially dangerous arrangement of the seat being up" - Wikipedia
You seem to be implying that their stars are colossal balls of gas and fire. For all we know, they could just be glow-in-the-dark dots painted on the inside of a ginormous sphere.
There's no need to sharpen my pencils anymore. My pencils are sharp enough.
Even the dull ones will leave a mark.
I've always liked the theory that Celestia was responsible for the stars aiding hr sister's escape.
Spooky.
Even then, it still has potential. We know what those things can do in the hands of void abominations, great commanders and archmages, against similarly powerful opponents, but we have no idea what'd they do in the hooves of Mr. average pegasus in the middle of Canterlot.
Trixe is an Archmage? I doubt it.
Life is simple: it has no nontrivial normal subgroups.
Perhaps "the stars will aid in her escape" had a double meaning. In addition to the literal stars that Twilight saw helping NMM escape, it was a reference to the Elements of Harmony helping Princess Luna return to her right mind.
That would be running a punchline into the ground.
Ooh, I like that interpretation.
There's no need to sharpen my pencils anymore. My pencils are sharp enough.
Even the dull ones will leave a mark.
@Pan Yeah, I like that one too. It makes Celestia a clever chessmaster.
@Sereg We're calling the pony's world "Earth" now?

We do need a name for their planet as a whole, come to think of it.
"A toilet with the potentially dangerous arrangement of the seat being up" - Wikipedia
They don't call it Earth. Earth was one of the proposed names for the new Earth Pony land. "Earth" in the context of their world simply refers to the ground they walk on, not the planet as a whole.
Also, the ponies call it Earth.
Well, that's a pretty big coincidence. It's like finding an alien civilisation that call their planet Belgium.
"A toilet with the potentially dangerous arrangement of the seat being up" - Wikipedia
Watch your language, bud! This is a civilized forum here.
That would be running a punchline into the ground.