This is how Twilight and Starlight vs. Thunderwing goes in
[Twilight and Starlight are sent flying to a wall. Thunderwing then arrives and lands in front of them and furls his wings.]
Thunderwing: Misery, misery, misery. That's what you two have chosen. I offered you friendship... ...and you spat in my face.
[Thunderwing then mercilessly attacks Twilight, injuring her as Starlight watches in horror]
Starlight Glimmer: Twilight!
Thunderwing: [laughs evilly]
[Thunderwing kicks Twilight against a wall. Twilight tries to use magic to blast Thunderwing, but Thunderwing steps on her front hoof, which makes her scream in pain]
Thunderwing: You've used your last magic, Twilight. Had you not been so selfish, your student's death would have been quick and painless. But now that you've really made me angry... ...l'm gonna finish her nice and slow.
[He kicks her against the wall]
Thunderwing: [laughs evilly]
[Starlight gets up and begins to glow]
Starlight Glimmer: You are the fool, Thunderwing!
Thunderwing: Nobody calls Thunderwing a fool!
Starlight Glimmer: Twilight is more than what you think she is.
Thunderwing: Oh please, Twilight's just a weakling.
Starlight Glimmer: She's my teacher and my friend!
Thunderwing: After what happened with that village cutie mark and trying to change the past incidents, you still call her a friend?
Starlight Glimmer: Yes. And now, I will fight you for her honor.
Thunderwing: So be it!
Starlight Glimmer: Let's do this!
[They begin fighting]
[Starlight begins to gain the upper hand on Thunderwing]
Thunderwing: How can this be? I am the mighty Thunderwing.
Starlight Glimmer: Or so you think.
Thunderwing: I will defeat you.
Starlight Glimmer: Or will you?
[Starlight summons the magic of friendship and gains Rainbow Power and uses it to shoot Thunderwing]
Thunderwing: Where did you get this power?
Starlight Glimmer: Went to the Tree of Harmony. The place where the Elements were first discovered by Luna and Celestia.
Thunderwing: There's a Tree of Harmony?
Starlight Glimmer: Yeah. Just underneath the Everfree Forest.
Thunderwing: Then I shall destroy it and all that stand against me!
Starlight Glimmer: Oh, really? Well, how would you like it if every single pony in Equestria stood against you?!
[A huge army of ponies comes out of the shadows and they surround Thunderwing]
Starlight Glimmer: So you see, Thunderwing, all these poor defenseless ponies can still do things with or without magic. Not everything has to be magic to be perfect. Together, we will stand against the power mad tryant that is you!
[Thunderwing opens his chest, readies his laser breath, and readies his wrist guns, and unfurls his wings]
Thunderwing: No one defies Thunderwing!
Starlight Glimmer: Ah, but you haven't learnt the truth behind all this yet.
[Starlight uses her magic to project a video of Twilight and her friends using the Elements to defeat Nightmare Moon]
Starlight Glimmer: We will finish you like they finished Nightmare Moon.
[The ponies create a big strong beam of energy which hits Thunderwing, making him scream in pain]
Thunderwing: No! I will not be defeated!
[Thunderwing tries to push back the beam but the ponies make it stronger]
[Thunderwing is finally defeated]
Thunderwing: Alright, you win for now.
[Thunderwing unfurls his wings and flies away. Starlight floats to the ground as the ponies of Equestria cheer]
Starlight Glimmer: [gasps] Twilight!