Chapter 3: Fluttershy's Darkest Hour
Fluttershy's backed up against a tree as Dark Reaper's smoke encases her.
Fluttershy is now possessed and being controlled by Dark Reaper.
Rarity, who had died when Sapphire Blood and Rainbow Dash were fighting over her, walks out of some brush just in time to see Fluttershy.
"Oh, hey Flu-", Rarity is cut off by Fluttershy slams her hoof right through her chest.
"What are you doing Fluttershy!?", Rarity asks as she struggles to get Possessed Fluttershy's hoof out of her chest.
"My name's not Fluttershy anymore.............", Dark Reaper says quietly.
"Th-the-then who are y-you?...........", Rarity asks, trailing off.
"The name's Dark Reaper. Live it. Learn it!", she says with an evil smile.
Dark Reaper rips Fluttershy's hoof out of Rarity's chest.
Rarity starts shaking, "Release Fluttershy now you..........you.......you demon!", she yells.
Dark Reaper snorts, "No way!"
Rarity grits her teeth and gathers every last bit of energy her spirit has in it and then punches Dark Reaper.
It barely did anything, it just pushed Dark Reaper backwards. Dark Reaper rolls her eyes and winds up for a punch and punches Rarity as hard as she can.
'WHAP!'
Surprisingly, the punch only sends Rarity into a nearby tree. But, in the end, Dark Reaper (Possessed Fluttershy) gets what she wanted. Rarity crashes to the ground and dissolves into a pile of gray dust, which is quickly blown away by the spirit plain's constant breeze of wind.
Possessed Fluttershy smiles, showing her sharp teeth, and looks at a watch-like meter that Dark Reaper had had on.
The meter red:
Spirit count:5/20
Spirit energy:250/1000
Possessed Fluttershy chuckled, "Hm hm hmm........ only 1/4th of the way there!"

Fluttershy's Shadow Part 3
(continuing from chapter 3)
The next day. . . .
Fluttershy wakes up after 12 hours of being unconscious.
"What happened?", she asks herself as she sees the trees surrounding her burnt to cinders, "Maybe I should try to find the others again."
After walking through the hollowed-out oaks and birches around her for about 10 minutes, she finds a folded piece of paper. She sifts it out of the ash and opens it up. (Ghosts can manipulate physical objects in an environment) The note reads:
"Dear Fluttershy,
It's Dark Reaper. You proved to be useful after all. You got me close enough to destroy two of your friends, Rarity and Twilight Sparkle, the two most innocent out of you 6. It seems that you body could only support a possessing being for a short time, saying you blacked out shortly after "you" killed Twilight Sparkle. I'd like to thank you again for letting me take over your body for this feat. >

Thank you for all you deadly help,
Dark Reaper

Fluttershy gets so upset that "she" actually killed two of her best friends' spirits, she throws the note down and spits on it.
"I can't believe I let that bitch take control of me!", Fluttershy says to herself.
While she's in the middle of her problem, Apple Jack and Rainbow Dash poke their heads out from some brush a bit a way's from Fluttershy. They quickly withdraw when Fluttershy shoots her eyes in their direction, only for it to be a false alarm.
"Ok.", Fluttershy says, "She says I killed Rarity and Twilight Sparkle's spirits, I should see something around here pointing to their death." Realizing that its probably been hours since that incident, she says, "There's no use trying to find them. The dust has probably blown away by now."
Apple Jack and Rainbow Dash sneak over to where Fluttershy was, "Hey!", they shout.
Fluttershy looks up at them, "Oh hi you two.", she says with a sad look on her face.
"You ok?", Apple Jack asks.
"No!", Fluttershy shouts, "Does it look like I'm ok?!? I just got done being possessed and now I'm learning that I killed two of my best friends!"
Apple Jack frowns, "Well. You didn't kill Twilight Sparkle and Rarity. She killed them.", Apple Jack tells her.
Rainbow Dash butts in, "By the way, you, me, Pinkie Pie and Apple Jack are the only 4 ponies left in the group.", she says, "Jennie and Jamie got dusted about 30 minutes ago."
"Ruthless!", Fluttershy cries out, "She killed children spirits too?!?"
"Fluttershy...."
"Insolent!"
"Fluttershy!"
"Barbaric!"
"FLUTTERSHY!!!!", Rainbow Dash yells this time.
"What?", Fluttershy says, withdrawing away from Rainbow Dash.
"They are both 20 now......... They've been 20 for about 3 months now!", Rainbow Dash says, rolling her eyes.
"Oh.", Fluttershy says, "At least they weren't fillys anymore!"
"Yeah.", Rainbow Dash says.