Twilight stared at the six-keyed chest. She still had no idea what was inside, or how to open it, but she was starting to think whatever was inside might be important to being able to defeat Tirek more easily.
Well, the only option left was one she hadn't dared take until now. She really didn't want to damage it, but it might be too important to leave closed.
She blasted the little box with her full power, cracking it open by brute force.
Inside, glittering rainbow powers swirled toward her.
Oh yes, that would make things easy!
So we're not going with "Too powerful to need the Rainbow Power"? This one also works, but is certainly unexpected.
6579987
Eh, I figure it's nice for her to get even more OP.
Twilight be like:
Huh. So was Discord turned, did Twilight decide to take matters into her own hooves, or did Celestia just ask the new princess to take care of the problem in the first place?
Oooooh, Dis' gonna be good!
Wait a minute, Twilight already has the full power of the other princesses, and now we're adding the rainbow power on top of that?
Oh Tirek, I pity you...
That is this story's answer to everything. If something does not conform to your way of thinking, blast it with rainbows. What an important lesson for the children.
In the words of Rainbow Dash: "Rainbows! Rainbows, darling, rainbows!"
~KBO.
Angry Tree of Harmony declares "No Castle for You! Come back 1 year!"
6580061
Nah, Twi just took matters into her own hooves as soon as she learned of the problem.
6580072
It's not going to go well for him.
6580086
Brute force is always good.
6580121
As if she couldn't just make her own castle.
6580187
In my headcanon, this is how Rainbow Dash reads.
Not for enjoyment or for learning... but to be able to say she read it faster than anyone else.
But where did the chest come from if they didn't get it at the beginning when whey saved the Tree of Harmony?
6580217
Tree generated it anyway?
Magic?
Lack of continuity?
Keys, schkeys. Ya don't need them if you got OP alicorn powers.
Now the mane six are gonna blast Tirek to smithereens!
6580331
You really think it'll take six of them?
6580346
Personally, I hope one of these three things happens.
One, Tirek tries to drain them, but they're too strong for him to drain, followed by Fluttershy whupping his ass.
Two, Fluttershy has Discord so whipped already that he wouldn't dream of betraying her.
Three, Tirek drains them successfully...resulting in him popping like a balloon because it's too much.
6580394
Well, I thought of one situation where he'd drain them and then grow so cosmically large that he's in fact too big to harm Equestria, just like how you're too big to harm a bacteria...
6580426
And then the ponies use Rainbow Power to just restore the entire world's magic while leaving Tirek cosmically large?
6580435
Nah, that's why I didn't use that plan.
6580346
As much as I like solo beatdowns, I prefer that every one of the mane six destroy Tirek, so that all of them get credit for the battle.
And thus, with the rainbow powers now in their hooves, it's on to the big battle!
6580677
Or the big bug squashing...
An OP pony with OP rainbow magic. What could go wrong?
7242825
Everything or nothing at all.