https://www.youtube.com/watch?v=mz1rqdfyGcg
Plays after driving off the Ceadeus. Even if you had help in the form of ancient weaponry, you still took down a sea-dragon larger than your base camp. You broke the mighty horns that caused earthquakes every time he rammed the ocean. You dodged torrents of water that would have ended your life not too long ago, and you made a dragon, who is deserving of the name "sea god", one that the Guild would need to send an army after, run away. And in doing so, you save Moga Village. In-story, the final cutscene marks this as your crowning achievement. A masterwork of bravery and skill that will be Spoken Of Forever.
https://www.youtube.com/watch?v=XyFfoFTs9P8
This one is from Satan's pet picklesaurus.