(In a doomed timeline)

In a dark and corrupted version of the crystal empire, a mad tyrant sits on its throne surrounded by the bodies of Equestria’s defenders and heroes. Only two now stand against this tyrant. The former Princesses of Equestria, Celestia and Luna.

As the Tyrant sat on her throne Celestia and Luna, heavily wounded, are in hiding while thinking of a strategy “Tis hopeless, she outmatches us.” Luna said, defeated.

Celestia looked at her sister then looked down “You might be right, alone we have no chance, but-” Celestia said, pulling out a small box she had kept hidden. Inside were two earrings.

“Mothers earring? What shall we do with those, peace offerings?” Luna scoffed.

“She may have taken everything from us but...she also gave me some knowledge. These-” She started explaining as she put on the earring on her right ear. “-are Potara’s if you put on one the other ear we will fuse into a powerful warrior.” Luna slowly reached out for it and grabbed it.

As she was about to put it on asked an important question “How long will this fusion last?”

“The fusion should be permanent.” And with that Luna stopped.

“Permanent.” Luna simply said as she contemplated if this was worth it. After a few seconds she sighed and said “we do this for the fallen” and with that, she put on the Potara on her left ear.

In a flash of light Celestia and Luna were gone, out stepped a new being, Eclipse and with her first steps, she paused. Glancing at her surroundings than at her own hand, she closed it feeling her strength, but as she did so she also realized a dark thought. One that would have to wait till after her victory. Eclipse opened her wings and flew into the sky towards the crystal tower.

In the Throne room, the Tyrant raises from her seat, slightly interested at the Alicorn standing in front of her. “My my, using Potara to stand a chance, that is interesting.” the Tyrant said.

“That's right you monster!” Eclipse declared. “It's time you died, For Twilight, and everyone you’ve killed.”

The tyrant chuckled “Neither of your previous selves could even stand up to final form Frieza from Namek. Maybe this gives you a chance against Semi-Perfect Cell, but me?” The tyrant powered up “I’m in a whole different ballpark.” and then the battle started.

You could be a bit more descriptive of what Eclipse looks like. And that last paragraph makes no sense. If Eclipse split apart isn't a match against Frieza's final form, how can she be on par with semi-perfect Cell, who is stronger than Frieza?

nice idea

7402841 Tis a solid idea, but it needs more of a hook... a polish. It's rough around the edges and a bit hard to chew and digest.

7402870
The Tyrant doesn't actually know how strong Eclipse is, They are making an assumption based on an old Fim headcanon that the community had where Celestia wasn't strong enough to fight Frieza... I might be miss remembering it but the Frieza the community was claiming was first form Frieza.

As for how does two beings who can't stand to Frieza's final form beat semi perfect cell. Well, I'm pulling numbers out my ass tbh.

7402887
Any suggestions to fix it?

7402912 Well, with a crossover, it's trickier to get that polish. What I'd suggest is have some build-up to the tyranny even happening; a demented game by Frieza wherein most everybody loses, despite their best efforts, and then the actual tyranny happening. That would also be the hook, and kill two birds with one stone.

Y'know, something leading up to, and justifying, the desperate fusion.

7403120
okay, that would not work for a few reasons.

first: This Prologue is meant to be the end of another story (untold but still its end)

Second: the Tyrant isn't Frieza, not even close

And third: The fusion is already desperate as I mentioned in the first line everyone is dead apart from Celestia and Luna

7403202 Oh, alright. That would make sense, then.

7403219
Any other advice?

7403225 Hrm... is the first story up? I'd like to read that to make sure I'm fully caught up.

7403235
oh no that first story doesn't exist, it meant to be told in flashbacks and exposition in the actual story, this is just setting up something for later

Ah