Sum of our Sins is a action adventure My Little Pony: Friendship Is Magic fanfic written by the-great-grey and based off the Majin Buu saga of Dragon Ball Z. Revolving around Twilight Sparkle, five months after she defeated Tirek.
It begins with Celestia and Luna being visited by a old pony, who tells that he found a powerful magical artifact known as the "Seed of Sin". Celestia knowing of the artifact sends Twilight, Luna and Rainbow Dash to find it and destroy it. The being inside of it gets released, and the main cast has to struggle to defeat it and save the world.
This My Little Pony: Friendship Is Magic Fanfic contains examples of the following tropes:
- Alas, Poor Villain: Celestia states that even after all the torment Discord gave onto others, his final act of giving his life up to protect Fluttershy, was extremely noble. And earned her respect.
- Always Someone Better: Luna hates Twilight after the events of the Tirek battle, but really she's hated Twilight for quite sometime now. She says the reason is she always felt second best to Twilight, in both Celestia's heart and in power.
- Anyone Can Die: It would be easier to list who doesn't die. Luckily they can all be revived.
- Curb-Stomp Battle: Every single fight against the God's Sin. No wonder Celestia thinks that they're all going to die.
- Death Is Cheap: Anyone killed by the God's Sin can be revived by the Tree of Harmony.
- FaceHeel Turn: Upon receiving more power from the Seed of Sin, Luna turns into Nightmare Moon again, with the sole purpose of killing Twilight.
- Fusion Dance: The Cutie Mark Crusaders have to do this to defeat the God's Sin. The only problem is they'll be like that for the rest of there lives. They end up agreeing to do it and they become a mare named Crusader.
- Merger of Souls: Discord, upon his death states that he wants to protect Fluttershy for the rest of her life. This causes him to merge with her at the last second. Besides a few new features and powers, she's still Fluttershy.
- Super Mode: The royal sister's normal, tall, sparkly forms are this. Twilight reaches this form when she is in a fit of rage after finding out Rainbow Dash had been absorbed by the God's Sin. Turns out in this universe every race can ascend to a higher form, if they just break their body's magical limits. It's also worth mentioning that the Rainbow powers are used like this.